What do fish eat?

[paul b]

Just some of my observations:

 

Oddly enough fish in the sea do not eat flakes, bloodworms, mosquito larvae, mysis, brine shrimp, squid tentacles, fish fillets, or pellets.

 

They eat what they were designed to eat and they only live in the areas where those foods come from. If a fish is in the one or two percent that is lucky enough to actually makes it to adulthood it probably means that it has learned a couple of things, one is to evade predators and the other thing is to find the food that it needs every day and not just once a day.

 

Most fish eat a very little bit all of the daylight hours and the rest eat only at night. Having good eyesight is not as big a deal for a fish as it is for us. They get along quite well with just one eye or in total darkness and they have evolved to eat a certain type of food that it needs for its particular physiology.

 

 

 

A fish like a mandarin was built to take advantage of a food source that most other fish of that size will not even notice. But such an active fish as a mandarin needs a lot of food and just about all it can eat are pods and other creatures about the same size. Pods are invertebrates and therefore mostly shell with a little

[trockafella]

Good read.! Thanks Paul.!!

[Saltwaterworx]

Hmmm...... nice!

[Swimboy123]

This should be pinned

[surf&turf]

Great info.

[OUsnakebyte]

As usual, I agree with much of what you have to say, but I think there needs to be some clarifications...

 

 

Pod shells are mostly chitin like our fingernails and have almost no nutrition except for maybe some calcium.

 

Our fingernails are made of Keratin, not Chitin, FYI. There is a difference... Unless you have lobster claws for hands...

 

 

 

Fish with long snouts like Long Nose Butterflies and Copper band Butterflies evolved to take advantage of a food source that resides in holes in rocks. These snouts are a disadvantage to these fish when it comes to defense or swimming because their jaws are weak and fragile. Their teeth are very small to fit in such jaws and are only suited to eat small soft foods like worms and tiny shrimp.

 

These types of fish need a large part of their diet to be oily like worm flesh is and is one reason these fish do not live as long in captivity as many other fish.

 

Is there a link for a reference for a study like this?

 

 

 

All fish have a liver which serves two purposes. The main purpose is the same reason we have a liver, to cleanse our blood but the other reason is buoyancy. Oil is lighter than water and the oil in their liver allows the fish to be almost neutrally buoyant. Their swim bladder is used for more delicate adjustment of buoyancy but the liver is the main organ that keeps fish from sinking like a rock. Without a liver and swim bladder even us humans would be able to swim better than a fish because we have quite a lot of air spaces, fish do not.

 

This contradicts what I leaned about fish biology. While it's true that the liver does store lipids that can help maintain buoyancy, I learned that the swim bladder is the main organ responsible for maintaining buoyancy and that "lipid stores may contribute relatively little to buoyancy in the majority of bony fish species." This would also support observations seen in the hawkfishes, for example, who do not have a swim bladder, have to swim constantly to stay up, and thus perch on corals/rocks when not swimming.

 

Now, cartilaginous fishes, like sharks, have no swim bladder, and their liver can be up to 30% of their total body weight and certainly aid in buoyancy. But, what do sharks constantly do? Swim. If they stop, they sink (and also cannot breathe).

 

If this has changed (swim bladder not responsible for majority of buoyancy), please let me know. But, this is what I learned.

 

 

 

This fish oil is also invaluable to a fishes health as fish do not have fat like mammals.

 

Fish don't store fat for reserves...? Also news to me, especially in particularly "fatty fishes" like salmon and herring. But, ever seen a fish after it has been shipped from the Pacific and is skinny? I was under the impression that this was b/c their fat reserves had been depleted during holding and shipping and more holding...??

 

Again, let me know if I am off base here...

 

 

 

Being cold blooded animals a fish can not utilize fat because it would remain solid at the temperatures in a fishes. Out 98.6 degree temperature allows up to eat solid fats.

 

(But fish oil is also much better for us to eat in small quantities in stead of solid fats)

 

Again, I don't.... what? I'm not clear as to what you are saying here. Are you saying that if a fish eats fats it cannot utilize them? Cold blooded animals cannot use fats how...? Or they cannot use stored fats? They don't store fat reserves?

 

Fish have a liver. This liver produces bile, which is a fat emulsifier - breaks down large fat droplets into smaller fat droplets to increase the surface area - that aids in fat digestion, which would happen in the intestines (probably utilizing lipase or something like it, but we are nearing the end of my fish biology knowledge). While this process does happen faster at higher temperatures, it will happen at lower temperatures - it just takes longer.

 

So, I can't see how fish are not able to eat and utilize solid fats. Once again, please, someone let me know if I am wrong or if research has shown otherwise.

 

 

 

I *think* what you are trying to say is that feeding a varied diet, trying to replicate close to what they would receive in nature, and feeding the whole animal instead of select parts is better nutrition for fishes. If that is the case, then I whole-heartily agree. In the zoo/aquarium setting, our nutrition department has not found one animal that does not benefit (health-wise) from feeding as varied a diet as possible.

 

Cheers

Mike

Edited March 31, 2011 by OUsnakebyte

[paul b]

Our fingernails are made of Keratin, not Chitin, FYI. There is a difference... Unless you have lobster claws for hands...

 

 

Oh No, Well some of the plankton is baby lobsters so I guess I am partially correct

 

Is there a link for a reference for a study like this?

 

As I said in the beginning, these are my observations from my 300+ dives, it is not a scientific study, just what I observed.

 

This contradicts what I leaned about fish biology

 

I guess your biology teacher was wrong A fishes liver could be 25% of it's body weight and most of that is lighter than water oil. The swim bladder is controlable by the fish to some extent (I think) but the oil in the liver is stagnent and is always there.

I am not sure of the exact degree of buoyancy the liver gives to the fish or if it is the same in all fish. The swim bladder and liver work together to help the fish float.

Sharks do swim very well with no swim bladder but without their liver they would sink like a rock. Not all sharks need to swim to breathe. Look at the nurse shark in the picture I took above. He could lay there all day, and he did.

I guess to see how much buoyancy the liver provides we need to remove the liver of a shark and see how he swims. The shark may protest though.

 

Fish don't store fat for reserves...? Also news to me, especially in particularly "fatty fishes" like salmon and herring.

 

Exactly, fish have no "solid" fat. They have oil. Oil is of course fat but I mentioned solid fat like you would find in an mammal. I eat fish every day and never found any solid fat. "Fatty" fish like makeral and salmon are full of oil. Not solid fat, The "fattiest" fish around is menhaden or moss bunker. They are very common here in NY and are harvested for their oil to make cosmetics. You can just squeeze them for oil. No solid fat.

If you squeeze a cow, you will not get oil, just solid fat.

A cold blooded fish has no use for solid fat because it would not liquify in their systems and they would probably get heart attacks from the accumulated fats in their arteries. Only oil could flow through a fish.

 

Are you saying that if a fish eats fats it cannot utilize them?

 

Except for maybe a piranna what fish would ever eat "solid" fats? Some pelagic sharks can but they are almost warm blooded. Some sharks like white sharks, bull sharks and mako's have warmer blood and they can and do eat mammals. Copperband butterflies would not have much chance to eat any solid fats so why would it have the ability to digest it? If you feed a fish like that solid fats you can see it being eliminated and not digested by the fish. As I said I am not a Dr. these are my observations.

I did not go to college, (war and all that)any little knowledge I have is from my observations under water and my fish and disecting.

 

I *think* what you are trying to say is that feeding a varied diet,

 

Actually I am saying to feed each fish what it is supposed to eat and close to what it eats in the sea. Beef heart is not an appropriate food for the reasons I stated. Each fish was specifically designed to eat certain foods, they are not all the same. If you keep Great white sharks you can feed cows, if you keep mandarins you need to have pods and tangs need greens.

 

Have a great day

Paul

[Jon Lazar]

Just to clarify, fish eat a lot of fish, but they also eat an awful lot of poop. We humans tend to visualize the whole ocean as being homogenous extensions of the near-surface reefs we're familiar with, with top predators chasing down their prey, but there's a lot of fish that live in the darkness below the epipelagic layer amidst a constant rain of fish feces. IIRC, fish digestive systems only extract something like 10-20% of the nutrients in whatever they eat, so their poop still has most of it's original nutritive value. I expect it's also a lot easier for a hungry fish to catch a slowly falling piece of poo than it is to chase down and eat another fish.

[paul b]

only extract something like 10-20% of the nutrients in whatever they eat, so their poop still has most of it's original nutritive value.

 

That is true because of the digestive system of a fish. Unlike us with our 20+ something feet of intestines a fishes digestive tract is very short and it does not seem to be a really efficient system but it works for the fish because any food that enters will stay there long enough to be utilized but if the fish has a chance to eat again, the food in it's digestive tract will just be pushed out and the new food will be utilized. That is the reason why you could feed fish every hour or so.

If you cut open a fish you will see the short intestines.

So most of the time fish poop is fairly nutritious.

All deerer water fish need to eat what little food they find and most of that is other fish. There is no algae past the first few dozen yards of water so fish need to get all the nutrition from that food source. But that is what they were designed to eat. Fish being cold blooded need very little food because they don't have to waste any energy generating heat. We put out about as much heat as a 100 watt light bulb which is a lot of energy. Fish can use all of their energy for growing, swimming, producing eggs and making threads like this possable

[El Camaron]

very interesting points Mike, and thanks for the write up Paul.

[OUsnakebyte]

I guess your biology teacher was wrong A fishes liver could be 25% of it's body weight and most of that is lighter than water oil. The swim bladder is controlable by the fish to some extent (I think) but the oil in the liver is stagnent and is always there. I am not sure of the exact degree of buoyancy the liver gives to the fish or if it is the same in all fish. The swim bladder and liver work together to help the fish float.

LOL... okay. Where did you hear/read that the liver is the major buoyancy control organ?

 

Well, I cracked open Scott Michael's Reef Fishes Volume 1, and there are several paragraphs dedicated to the swim bladder and its function in buoyancy control. There was no mention of the liver, but maybe he just forgot.

 

I did find an excerpt from this book here - Handbook of Fish Biology and Fisheries

In this excerpt, the author states, "In general, lipid stores may contribute relatively little to buoyancy in the majority of bony fish species." He goes on to say, "Gas is the most efficient material for providing lift, and most teleosts possess gas-filled swimbladders."

 

This is of course why you fill your BC with air and not oil when diving... (that and air is much easier to tote around...)

 

Again, yes, lipids do contribute some to aid buoyancy (this might be more true for deep water fishes, say, 400 meters), but the major organ for this is the swim bladder. I spent more time than I care to admit today to see if I could find information contrary to this but came up empty. If there is information supporting that the liver is the main buoyancy control device for reef fish that also have swim bladders, I very much want to read it. But, give me a book, paper, article... something.

 

 

 

 

Sharks do swim very well with no swim bladder but without their liver they would sink like a rock.

Paul... if a pelagic shark stops swimming, it will sink - with or without a liver. As I said before, it does help with buoyancy. I hate quoting Wikipedia, but... oh well...

 

"The liver constitutes up to 30% of their body mass.[16] The liver's effectiveness is limited, so sharks employ dynamic lift to maintain depth, sinking when they stop swimming."

 

Shark wikipedia - sorry, it's the best I can do right now

 

 

 

 

Not all sharks need to swim to breathe. Look at the nurse shark in the picture I took above. He could lay there all day, and he did.

I guess to see how much buoyancy the liver provides we need to remove the liver of a shark and see how he swims. The shark may protest though.

Yes, I know that nurse sharks and some reef sharks can remain still and still respire, and nurse sharks are probably the most famous for that. My point was that if they stop moving, they sink b/c the liver is not enough of a buoyancy compensator to maintain a neutral state. And, where do sharks rest when not moving? On the seafloor, not in a neutrally buoyant state.

 

 

 

 

Exactly, fish have no "solid" fat. They have oil. Oil is of course fat but I mentioned solid fat like you would find in an mammal. I eat fish every day and never found any solid fat.

Solid fat is stored as adipose tissue in animals (in mammals, birds, reptiles, amphibians, and... fish too?) I wasn't so sure about this, so I sent an email to the head of our staff pathology department (he is a really nice guy). Basically, I asked if marine fish store solid fat as adipose tissue or is it all stored as oil. Copied below is his reply:

 

"Oh they definitely store solid fats. I do not know the particulars of the types and chemical composition of the different types of lipids but that likely could be found in the arcane literature on the net. They store a lot beneath the skin, along the midline on both sides and around viscera and in the liver. It's less prominent between the individual muscles but microscropically it's still there."

 

 

 

 

 

"Fatty" fish like makeral and salmon are full of oil. Not solid fat, The "fattiest" fish around is menhaden or moss bunker. They are very common here in NY and are harvested for their oil to make cosmetics. You can just squeeze them for oil. No solid fat.

If you squeeze a cow, you will not get oil, just solid fat.

I just googled "Salmon Adipose Tissue" and found this (remember, adipose tissue is solid fat, not oil):

 

Salmon Adipose Tissue Research

 

Yes, they do have oil, but they also have solid fat - as do other fishes. And that chick is kinda hot...

 

 

 

 

Being cold blooded animals a fish can not utilize fat because it would remain solid at the temperatures in a fishes. Out 98.6 degree temperature allows up to eat solid fats.

 

A cold blooded fish has no use for solid fat because it would not liquify in their systems and they would probably get heart attacks from the accumulated fats in their arteries. Only oil could flow through a fish.

If I am reading this correctly, you are suggesting that b/c of the lower body temperature (i.e. less than a human's 98.6F), a fish cannot properly digest solid fats...? Perhaps it's a stretch, but would this then apply to all ectotherms...? (i.e. snakes, amphibians, etc.) Of course, that's not true - we know that snakes can digest solid fats when they eat mice and rats. And, they are digesting adipose tissue anywhere in the 60s to the 90s, depending on species. But, snakes do not have any extra organs for this than a fish does - a liver, pancreas and intestines.

 

 

 

 

 

Except for maybe a piranna what fish would ever eat "solid" fats?

Well, presumably any piscivorous fish.

 

 

 

 

Some pelagic sharks can but they are almost warm blooded. Some sharks like white sharks, bull sharks and mako's have warmer blood and they can and do eat mammals.

Yup, many sharks to have the ability to keep their blood temp higher than the surrounding water. White sharks typically inhabit waters 55-70 or so degrees F (with variations, of course). I have read that they can maintain their temperature some 15-20 degrees F warmer than the water. But, even at it's peak, it is still lower than our 98.6F and have no problems with solid fats. So, perhaps this is a better analogy than the snake reference above about a fish (ectotherm) being able to digest and utilize solid fats.

 

 

 

 

 

Copperband butterflies would not have much chance to eat any solid fats so why would it have the ability to digest it? If you feed a fish like that solid fats you can see it being eliminated and not digested by the fish. As I said I am not a Dr. these are my observations.

I did not go to college, (war and all that)any little knowledge I have is from my observations under water and my fish and disecting.

Actually, crustaceans often have waxes (which would fall under solid fats) in their tissues. But, how much fish utilize these waxes, I can't say right now. I would definitely have to research this more.

 

 

 

 

Actually I am saying to feed each fish what it is supposed to eat and close to what it eats in the sea. Beef heart is not an appropriate food for the reasons I stated. Each fish was specifically designed to eat certain foods, they are not all the same. If you keep Great white sharks you can feed cows, if you keep mandarins you need to have pods and tangs need greens.

When you quoted me, you left off the second part of my sentence in which I said, "...trying to replicate close to what they would receive in nature,..." I never suggested dumping a steak into your tank. I also gave reasons for feeding the variety of foods, as you also correctly stated.

 

 

Cheers

Mike

Edited March 31, 2011 by OUsnakebyte

[paul b]

Wow, I love this, I get the opportunity to do a lot of typing.

 

Where did you hear/read that the liver is the major buoyancy control organ?

 

 

I did not read that anywhere. I do my own research and learned what I know from diving and keeping fish, although I am a compulsive reader. Also my family has been in the sea food business for over 200 years (I am not sure of the exact number of years but I know it is over 100) Anyway if you fillet fish you will see the huge liver in almost any fish. If you squeeze it, you will find it full of oil. Oil floats so I came to the conclusion that it helps fish float because if you take 20% of a fish and make it lighter than water it will help the fish float to some extent. I did say the liver is used mainly to clense the blood and the floating part just accidently happens as a side effect of the oil. I know the other large organ that you will find in that fish, the swim bladder is the main "floating" organ so I am agreeing with you.

 

Well, I cracked open Scott Michael's Reef Fishes Volume 1, and there are several paragraphs dedicated to the swim bladder and its function in buoyancy control. There was no mention of the liver, but maybe he just forgot.

 

 

Scott Michael is an intelligent guy and knows alot about fish but I don't know how many fish he has taken apart. You need to study large fish so you can study their organs.

As I said it is not important that the liver floats, it is just a side benefit of having a liver but oil floats. I know because I feed it to my fish every day and it makes an oil slick.

 

This is of course why you fill your BC with air and not oil when diving...

 

And the stuff really stinks so you will not get any girls to dive with you.

Also sharks really like divers wearing 20 lbs of fish oil.

 

but the major organ for this is the swim bladder.

 

I agree with that. But the oil "helps by accident" It was not my point to mean that fish have oil only to float. They have a liver for the same reason we have a liver. We have sinuses. They help us float, not much but a little I assume. I am sure we don't have sinuses to help us swim but they are there for something else, although I really don't know what.

 

Paul... if a pelagic shark stops swimming, it will sink - with or without a liver. As I said before, it does help with buoyancy. I hate quoting Wikipedia, but... oh well...

 

 

Yes sharks do sink, I have dove with them many times and laid on the bottom next to them.

The liver helps them sink more slowly but like I said the liver is there mainly to clean their blood.

Also Wipedia is a great source of information but the guy who wrote it may not necessarilly know a shark from a rhinoserous, he may be a vegetarian and probably never took apart a shark. I eat theem all the time. Thair liver is huge.

But I know they sink.

By the way I love this conversation although I am not sure what you are argueing with me about.

 

My point was that if they stop moving, they sink b/c the liver is not enough of a buoyancy compensator to maintain a neutral state. And, where do sharks rest when not moving? On the seafloor, not in a neutrally buoyant state.

 

 

Yes, they certainly do sink, no arguement there. I never said they can float, I said their liver "aids" in buoyancy but it does not fully make them buoyant. A shark is designed with slightly upward facing fins to keep them in the water column when they are moving.

When I dive my BC also aids my Buoyancy but being I am a lobster diver I want to sink, and I do. Just like a shark, A slightly over weight bald shark.

 

"Oh they definitely store solid fats. I do not know the particulars of the types and chemical composition of the different types of lipids but that likely could be found in the arcane literature on the net. They store a lot beneath the skin, along the midline on both sides and around viscera and in the liver. It's less prominent between the individual muscles but microscropically it's still there."

 

 

OK I have to give you that one. If a fish has some solid fat in their adipose tissue acording to arcane literature on the net, I can't argue with that. I do know that I have taken apart thousands of fish and have only found oil but I guess there may be some solid fat in there. That solid fat is not traveling around their arteries and If they do have some solid fat I believe it is insignificant. We also have some Kryptonite in us but not much.

Either way my main point was not that fish have solid fat but that they have a large amount of oil and it keeps them healthy. I do not have any literature on that but I do have a reef tank quite old with most of the fish spawning. Before I starting suplimenting with oil my tank was an ich magnet and nothing was spawning. After that in about 1975 or so fish started to spawn and I have not had to quarantine in 30 years. I can put ich infested fish in my reef with no worries about ich. I feel it is due to the oils I feed them that I know from my own research in my tank that pute fish into breeding condition which also (according to my research again) revs up their immune system so they do not get any diseases.

I invite you to bring me an ich infected fish and put it in my reef for a test to check my findings. I have done this dozens of times and that fish may die but the rest of the animals will be fine. If it is not from their diet I don't know what else it could be. Unless it is from my UG filter

I am sure Wipedia has no experience with an old tank feeding fish oil.

 

Yes, they do have oil, but they also have solid fat - as do other fishes. And that chick is kinda hot...

 

Very young for me but I do agree with you 100% on that

 

If I am reading this correctly, you are suggesting that b/c of the lower body temperature (i.e. less than a human's 98.6F), a fish cannot properly digest solid fats...? Perhaps it's a stretch, but would this then apply to all ectotherms...?

 

Thats why snakes lay in the sun and only need to eat every couple of months. They also don't move much so if they digest a rat in a month they have nothing else to do anyway.

If you keep a snake cold, it can not digest anything with fat, well maybe in a few months but I am not a snake expert. I did shoot a very large python and cobra in Nam but I doubt that makes me a snake expert.

 

Great debate, (If that is what it is. I enjoyed this but now it is time to go swimming. Talk to you later.

Have a great day

Paul

[OUsnakebyte]

As I originally stated, I agree (and usually do) with much of what you have to say in these "oracle reefer" moments. In this particular thread, some things needed to be cleaned up/clarified. The original three points I honed in on are copied below.

 

All fish have a liver which serves two purposes. The main purpose is the same reason we have a liver, to cleanse our blood but the other reason is buoyancy. Oil is lighter than water and the oil in their liver allows the fish to be almost neutrally buoyant. Their swim bladder is used for more delicate adjustment of buoyancy but the liver is the main organ that keeps fish from sinking like a rock. Without a liver and swim bladder even us humans would be able to swim better than a fish because we have quite a lot of air spaces, fish do not.

When I read this - "the oil in their liver allows the fish to be almost neutrally buoyant" - it sounds as if the other reason fish have a liver is for buoyancy, when in reality the lift provided by a bony fish's liver is negligible when compared to the swim bladder (see the link provided above).

 

And that the "swim bladder is used for more delicate adjustment of buoyancy but the liver is the main organ that keeps fish from sinking like a rock." These statements are factually incorrect.

 

 

 

This fish oil is also invaluable to a fishes health as fish do not have fat like mammals.

Again - "fish do not have fat like mammals." Incorrect. Yes, mammals store MUCH more adipose tissue than fish. But fish store adipose tissue as well. It finally came back to me when I remembered looking at histology slides of trout adipose tissue in histo lab. It just didn't make sense that their marine counterparts would not store solid fats as well.

 

 

 

 

Being cold blooded animals a fish can not utilize fat because it would remain solid at the temperatures in a fishes. Out 98.6 degree temperature allows up to eat solid fats.

Fish cannont digest solid fats. I have not found anything that leads me to believe this is true. So, I have to say incorrect also b/c solid fat digestion happens at various temperatures in ectotherms (cold blooded). Yes, snakes sit in the sun, but their body temperature does not reach 98.6F and even in the 60s, some still digest solid fats.

 

 

 

I do feel I should state that I think you have much to offer from your experiences over the last four decades, and there is much that you post that is good information and should be considered when keeping captive reef animals. But, I often see highly suspect conculsions, and in some cases factually incorrect information, and I feel it needs to be clarified/corrected.

 

Cheers

Mike

Edited April 1, 2011 by OUsnakebyte

[paul b]

Mike, I really didn't mean to propose that the fishes liver keeps the thing afloat. It doesn't matter in this discussion. I am sure that some fish have a larger liver than other fish and some float better but if the liver is 25% of many fishes weight and it is mostly oil than it has to help the fish float. Maybe minutely maybe a lot and I doubt there are any studies on it. It does not matter to me or the fish how it floats as long as it can swim. I know it's swim bladder is filled with a gas and it floats. If I stated that wrong then I am wrong.

Also fish may have some solid fat but they have mostly oil. I am sure if I look it up in a scientific journal I will read they have some solid fat but if they do, it is not much. So I should have said that the fat in a fish is mostly oil. I still don't think fish digest solid fats or need them. A tropical fish would never have the chance to eat an animal with solid fat. But if it does get the chance to eat a buffalo, elephant or aquarist I need to be there to observe this so I can see if it gets an upset stomach.

My post here and all of my posts are my observations, as a matter of fact the first words I mentioned at the top of this thread is that these are "my" observations. My observations can not be wrong because I did not state anything is a scientific fact or that I read any of it anywhere. It all comes from me observing, diving and eating fish for 60 years. I am sure If I look it up I can find fish that eat fats, coconuts, oldsmobiles and palm trees but in general they eat fish. I am sure you are correct they also have some solid fat as you found it in a scientific paper. I am an electrician and depended on my own experience to learn what I know.

How long did the guy who wrote the scientific paper SCUBA dive? Does he have a fish tank? Where did he get his information? Did he read it? if so, did the guy who originally write it have a fish tank.

I am sure these guys know what they are talking about but this thread and all hobbiest threads are basic generalizations and this is not a scientific forum.

And one thing. Everything I have ever written about fish and submitted to either a magazine or web site has been published. That does not mean that I know anything about fish but it does mean that anything can be published without any thought to it's validity. After all I am an electrician with absolutely no formal education about fish.

All I have is my 40 years of diving and my 40 year old tank that I am now going to feed hamburgers to.

And Mike, I really enjoyed this and welcome you or anyone else to contradict me as I am well aware that I am not the God of fish.

Take care and have a great day

Paul

[Jon Lazar]

Finally. Can we get back to talking about poop?

[paul b]

Finally. Can we get back to talking about poop?

 

 

If you promise not to look it up on Wipidia

[OUsnakebyte]

I still don't think fish digest solid fats or need them. A tropical fish would never have the chance to eat an animal with solid fat.

What? I… don’t… I just… (sigh - bangs head against wall, pinches corners of his eyes with index finger and thumb while shaking his head side to side...) Paul, you're killing me. Okay, let’s review the thread one more time b/c I'm sure everyone thinks we have not yet beat this dead horse enough...

 

You explained to us earlier that fish eat other fish – to which we all agree. You then told us that fish don’t have fat like mammals and that it is oil - remember squeezing the fish vs squeezing the cow? (solid fat = adipose tissue). This didn't make sense to me, so I contacted the zoo’s head veterinary pathologist, who explained that yes, they do indeed store solid fats – a point to which you even agreed.

 

Fish eat fish + Fish have solid fat = Fish have the chance to eat an animal with solid fat.

 

It’s contradictory statements like the one quoted above that drive me absolutely bonky………………. Seriously, is someone playing an April Fool’s joke on me today?

 

But, if you want another means to which a tropical fish might be exposed to "solid fats," then consider that many reefs have evolved in conjunction with mangrove forests. Baby birds often fall from the nest into the surrounding waters (your post of the piranha reminded me of that). Now, I would NEVER claim that the majority of reef fish diet is composed of baby birds from a mangrove nor do I believe we should all start chucking freshly-plucked chicken into our tanks, but this is just one scenario in which a fish just might be exposed to adipose tissue. But, we do know that mangrove forests are one way for reefs to receive natural influxes of nutrients.

 

Furthermore, I was just at happy hour with the aforementioned veterinary pathologist (and a few other vets from the staff), and I asked the question - just for clarification - "can fish digest and utilize solid fats." The answer was a resounding, "Of course! Why wouldn't they be able to?" (Tim is a really nice guy, and didn't make me feel too dumb for asking the question....)

 

 

 

 

My post here and all of my posts are my observations, as a matter of fact the first words I mentioned at the top of this thread is that these are "my" observations. My observations can not be wrong because I did not state anything is a scientific fact or that I read any of it anywhere. It all comes from me observing, diving and eating fish for 60 years.

After 40 years of reefing and 60 years of living, you have made several EXCELLENT observations. You have then formulated various hypotheses and attempted to find evidence and support for the developing theory. This is all great, fine and dandy.

 

What I am calling into question is not your observations (whether diving, you dissected and/or ate a fish or have had a reef tank for 40 years) but rather your conclusions. The conclusions of fatless fish and the liver out-performing the swim bladder for buoyancy function are just dead wrong conclusions. That’s all – just the conclusions. And by the way, I do agree with many of your other conclusions.

 

 

 

How long did the guy who wrote the scientific paper SCUBA dive? Does he have a fish tank? Where did he get his information? Did he read it? if so, did the guy who originally write it have a fish tank.

Seriously? I hope you are being facetious.

 

 

 

Everything I have ever written about fish and submitted to either a magazine or web site has been published. That does not mean that I know anything about fish but it does mean that anything can be published without any thought to it's validity.

Of course incorrect information can be printed (and nowadays even more easily posted on hobbyist forums....). But, that's what the peer review process in journals and the editorial process is supposed to limit. That's also why you see "Editor's Notes" sometimes inserted - they need to clarify something or partially correct a generalization, for example. If it's really bad, expect a retraction. But, consider your soucre - i.e. the supermarket tabloids vs. National Geographic.

 

 

 

I am sure these guys know what they are talking about but this thread and all hobbiest threads are basic generalizations and this is not a scientific forum.

Of course, this is a hobbyist forum, but it doesn’t mean that we should spread misinformation or cannot be held accountable when something wrong is said. I would expect to be corrected if I said that the world is flat, the moon is made of cheese, or that the BCS is the most legitimate means of determining a college football champion.

 

I don't think everyone needs a PhD to post here, nor do I think everyone has to reference peer-reviewed articles to state a conclusion. Heck, a simple google search cleared up the misinformation about salmon not having adipose tissue AND I found a hot European science-chick with the same click!

 

I say this with respect and kindness - Paul, you in particular need to be careful of what you write and how you phrase your thoughts. With your lengthy time in the hobby, many people are going to look up to you and take the information you give as factual, without ever questioning it (whether right or wrong, many people are sheep and will blindly follow). And, as I have said, there is a lot of good information you do have to offer. But, you - perhaps more so than others, whether fair or not - need to be careful when you say things b/c someone, as posted above, IS going to take it all as fact and then claim it should be made a sticky for all to read and see when you have in fact posted things that JUST ARE NOT TRUE.

 

 

 

If you promise not to look it up on Wipidia

Okay, okay... I fully admit that I should not have referenced Wikipedia. I was in a hurry and didn't have time to hunt. I never let my students cite it in their research papers; nor should I. My bad.

 

I realize it is superfluous and at this point I'm sure no one cares, but here is a book that talks about shark buoyancy.

 

Shark Buoyancy

 

But, it wouldn't really be fair if I didn't correct myself, now would it...? Above, I made it sound as if ALL sharks will sink if they stop swimming. Apparently, according to the author of this book, "some deep-water sharks have enough liver oil to achieve perfect neutral buoyancy, but they are the exception." So, I now stand corrected too.

 

But even more important than that, I just learned something, which is pretty cool.

 

 

Cheers

Mike

Edited April 2, 2011 by OUsnakebyte

[paul b]

What? I

[OUsnakebyte]

If I did, I never meant to imply that someone needs a degree, or multiple degrees, to be a good observational biologist or contribute to our overall body of knowledge. The most famous example I can think of is Alfred Russel Wallace and Charles Darwin coming up with almost the exact same theories of evolution by natural selection at almost the same time, despite vastly different backgrounds. I think it is a wonderful story. I could care less if you are an electrician, astronaut or professional wrestler.

 

I realize that I might nitpick on fine points, but... it's a habit I have grown to have after a few years of grading papers, and I am a natural skeptic. Perhaps I should be more fastidious at pointing out things I DO agree with in lieu of only pointing out the things I question.

 

 

I was away the day you came to speak at the club, so I am sorry I missed your talk. Since this started as a "what do fish eat" thread, I'm wondering if you would mind posting any fish food recipes you use (I think you may have done this before, but I can't remember) and, if possible where you get the ingredients - regular grocery store, asian food markets, pull straight from the ocean, etc. I realize the foods and recipes may vary given the variety of fishes.

 

Cheers

Mike

 

Oh, and blood pressue is returned to normal...

Edited April 2, 2011 by OUsnakebyte

[paul b]

I was away the day you came to speak at the club, so I am sorry I missed your talk.

Mike if you were there I would have had to get my facts all straight

But the talk was on the history of the hobby and I was there for most of that so it was easy.

 

I'm wondering if you would mind posting any fish food recipes you use

 

I don't use any recipies but I do feed live black worms every day for the oil (but I don't know if it makes them float)

I have found, and it is only my opinion, that the oil in live blackworms for some reason that I do not know, greatly helps fish get into breeding condition. I have also found that fish in that condition do not get sick "In my tank anyway".

I also feed fresh clams that I freeze. I buy a live chowder clam, open it and freeze it. I then just shave off thin slices, these I use to feed the fish, the LPS corals and the crustaceans. Clams I feel are a good food because you can feed the entire animal with the guts. I also feed mysis or plankton.

I keep a small container and I put 20 or so sinking pellets in it in the morning. To that I add 2 drops of fish oil that I squeeze from a fish oil capsule (That I take myself, they help me float when I swim but I won't go into that )

After a while the oil is soaked up and I shoot a few of those to the spawning gobies in the back that never come out any more due to their eggs.

I sometimes squirt some of those pellets in there at night for the night eating fish.

I don't mix up too many oil soaked pellets because fish oil goes bad in the presence of oxygen which is why it is not normally in commercially sold foods. The oil itself is sold in air tite capsules.

In the summer I collect amphipods, sponges, seaweeds and tiny fish for food.

Fish eggs like salmon from an Asian store are great but not easy to keep. They don't freeze great and don't last long. Also just a couple of eggs will make your skimmer overflow so they need to be rinsed for like five minutes.

Edited April 2, 2011 by paul b

[OUsnakebyte]

(That I take myself, they help me float when I swim but I won't go into that )

 

HA HA HA HA HA!! Now THAT was funny! Nice...

 

 

I keep a small container and I put 20 or so sinking pellets in it in the morning. To that I add 2 drops of fish oil that I squeeze from a fish oil capsule After a while the oil is soaked up and I shoot a few of those to the spawning gobies in the back that never come out any more due to their eggs.

I sometimes squirt some of those pellets in there at night for the night eating fish.

Soaking pellets with oil from the capsules. Never thought of that - I'll give it a try.

 

Cheers

Mike