Banggai Cardinal Spawning Log

[DaJMasta]

Now, after that update and doing it a couple of times, let me make some recommendations for someone wanting to raise these guys to help get success sooner:

 

When you have a pair and the female starts doing the dance, you probably have a day or two until they spawn.  Spawning is extremely fast (a few seconds) and then the timer begins.  When they've spawned the male's jaw will be much more pronounced and full than before, but he may be able to fully close his mouth and not show any eggs.

 

At my tank temperature of about 26.5C, they take almost exactly 3 weeks for the eggs to mature and hatch, and you don't always see little faces in his mouth to know when the time is coming.  My recommendation would be at the 19 day mark to catch him, provided his cheeks still look puffy and he is still ignoring food, and leave him alone with some shade in a breeder box in the original tank.  It will then likely take a few days (2-5 maybe) for him to spit them out as fry, and you're likely to get an early one or a few before you get the big release.  He will open his mouth fully if you can catch it, but you will likely see a lot at once and the remains of the egg mass in the breeder box (since the clean up crew can't get to it and the flow is very low) that will signal the end of the hatch.  You can leave him in there overnight to be sure everyone is out, but make a count of the fry when it looks done.

 

Return him to the main tank after that day of recovery time, especially if his activity has perked up a bit and his mouth has returned to normal shape.  He should resume eating another day or two after being returned to the tank.  Around the same time, or when he's been removed from the breeder box, you can start feeding the fry, and the best food is going to be live copepods.  They won't eat much until they can swim and hunt, so if you see them mostly swimming a bit and then resting on the bottom instead of staying afloat for a long term, they may not yet have developed their swim bladders and may not be ready to eat yet.

 

You can probably raise the fry in that breeder box for a few weeks, even, but they will eventually need more space and more flow.  I'd feed live copepods daily, then you can start with a very fine prepared food once you're sure you've seen a feeding response (and the fry sort of snap at the food when they eat, like their parents), but for something like TDO A which floats pretty well, I find it best to mix with water until it can disperse, then give it to them - maybe even at the same time as the live food to get them to try it.  I try to feed several times a day, but I think ideally, you feed live food at least twice a day, then can introduce prepared foods whenever.  In an established system they will have some other food (especially if you're also dosing phytoplankton to the system to promote growth), but live food is going to be the thing they eat most reliably, and feeding multiple times a day increases survival and growth rates, even if a large dose of copepods once a day may suffice in some cases.

 

Transfer the fry to a low flow aquarium with mesh covers over any pump or overflow intakes to keep them from going in, and for anything with a reasonable bit of suction, it's good to have a larger bag or sponge over it to keep them from being pinned against it by the flow.  I just use a regular tank for this with an established filter/CUC/etc. but no livestock, but not too large of a tank will help.  Basically, the fry are inefficient hunters, so rather than raw quantity of live prey for them, you need a certain prey density in the volume so that they are able to eat enough of what's there to get what they need.  That means in a larger rearing tank, you need to feed more, and you need to buy/culture more copepods.  Slowly increasing the size of prepared foods as they grow keeps them growing quicker and eating well, and adding the prepared foods into a water stream so they move a little more like live foods initially seems to help them snap them up.  Eventually you can put food in a feeding ring and they will realize when you are feeding and where to go, but this is probably at least a month in.  Again, flow under the feeding ring helps entice them a bit.  They will occasionally bicker with each other, and when threatened they will try to hide in something (sea urchins in nature, but branching macroalgae worked fine for me), but I don't think they're much of a risk to each other and they will be swimming freely basically all the time now.

After something like two months, it's probably good to put in some extra flow - a nano sized powerhead or pump would work, but again if there are not many intake slits it may be good to use sponge to keep a little distance from the intake.  They should be fairly strong swimmers now and you'll see them chasing food particles at longer distances.  You can also introduce frozen foods or other more normal sized tank foods - they won't be able to eat big chunks yet, but their mouth is bigger than they look, and late in this second month a smaller hikari mysis is something one of the larger ones could realistically eat.  Around three months in, you should have a decent percentage of them over an inch long, and while waiting longer will increase the likelihood that they do well in a full-flow aquarium with larger fish, it's at this point I think they have a pretty good shot.  Normal small sizes to find in stores probably have another month or two worth of growth.


And that's what I can offer so far!  Having a separate tank or low flow zone for them is very helpful for growing the fry up, but you can do a lot of the early stages with just a breeder box.  Live copepods are really a critical part for nutritional success, I think, so while you can buy them, you will likely want to culture them and have supply on hand, and that culture will take time to mature - a month or so starting from a commercial pack of copepods, growing it up to a gallon jug size, and then harvesting about 10% daily and replacing the volume with live phytoplankton (or seawater and whatever you're feeding yours).  Apocyclops pods have been the easiest for me to culture in quantity and for long periods, and with relatively high air bubbling through the culture and live phytoplankton, you can get and maintain pretty impressive culture densities without anything fancy.

Edited January 24, 2022 by DaJMasta

[DaJMasta]

The male spit out his latest batch of kids today, and I learned a bit more:

This time, he faked me out.  He spit out four, then two more with the egg mass, and then nothing overnight.  So I figured it was a small spawn, and I let him back out of the box.... only to see his mouth still full and then several little sliver and black specks in his mouth when I looked.

Took another 20 mins to chase him back into the trap and put him the box, and this evening he spit out the rest... 34 in total.  Not only that, I let him back into the main tank and then fed everyone, and he ate at least bloodworm within about 30 mins of spitting them all out... he was obviously hungry.

In the last week or so he had repeatedly made a quick dash towards a piece of food at feeding time only to slow down and turn away at the last second, presumably remembering the babies in his mouth.  All told, though, I think he's had less than a week of normal feeding time in the last two months, so he did a remarkable job holding so many for this time after such a short turnaround from the last.  Not only is this the highest quantity I've got from this pair, but I think it's the highest success rate - judging from the number of what look like failed eggs that came out in the box with the babies, there were probably just under 40 eggs in the group, meaning almost a 90% hatch rate for the clutch.

 

 

Got the babies caught and released in the grow-out level of my little rack, and there are lots of copepods available.  I moved last spawn's babies out of the level and into the upper one (more flow and other critters, including anemones) and while 10 of 11 survived the month in that mid level, I've lost 4 since moving them up, so I'm going to try to feed a bit heavier and maybe experiment with some extra flow in the mid level to try and condition them to survive in the later stages.

[DaJMasta]

Notes from the latest batch:

The fry seem to start going for the fines of frozen food at about a week old, so I've barely fed the current smallest ones any pellets so far (they do get some supplementally, but get frozen twice a day now).

I don't see much bullying among the siblings even with a 2x overall length difference (I moved some of the second youngest batch in with the oldest batch and they all acted the same), this may change at adulthood, but at least a few months in they seem to act nice to each other.

 

And most interestingly, they can pretty easily figured out what being fed looks like (where, when, etc.), and they can see a distance outside of the tank to know when to expect it.  When I go and feed my main tank (about 6-7 feet away) the juveniles all crowd over into the corner of the tank where they usually get fed.  More than that, if one or two gets excited and starts acting like there is food, all the other ones will notice, swim over, and start trying to eat anything nearby (I've seen them go into a feeding frenzy after a bubble got sucked into a powerhead...)


And even the youngest fry seem to have some of this behavior.  These guys won't see me working at the other tank, but they know where I usually feed and rush over when I do, and I've seen them ball up excitedly in one spot every so often in feeding frenzy mode.

 

They'll also try to eat food almost as big as their body size.  This guy eventually fit it all in there, even though half way in when I took the picture, he looked longer than normal already because of how much food was in there!

Their parents seem to have settled at about a ~31 day spawn cycle, about 21 days to hatch, about 3 days before they're all spit out, and a little less than a week for the male to eat before they spawn another batch... somehow, he seems to manage.

Edited May 25, 2022 by DaJMasta

[DaJMasta]

An unusual update after a bit:

My pair have spawned continuously since the last post, every month or so, and I haven't gotten a single fry out of it.

I'm not really sure what's been happening, but the most recent run may be shedding some light on it.  In the couple before now, I had noticed that it seemed like I was catching him later than I should, even though I was catching around day 20 or so which has been ok before, so I caught him on day 18 this time (yesterday), and before I did I thought I saw a baby in his mouth.

I noticed he was wary of being in the trap when I was close to it (same method/placement as previous tries), so I rigged some fishing line and closed it from a distance.  Worked fine, transferred into a mesh box in the evening, and before I went to sleep.... his cheeks and jaw were no longer puffed out, though there was no real sign of debris in the box.  In the morning, same story, with a small amount of brown debris (maybe egg sack residual), and he was willing to eat, so I let him out.

 

I think he's eating the eggs, maybe in response to being caught/moved, even though it's not long term and he doesn't actually get taken out of the water for the transfer.  If this is the case, it may be pretty tricky to get more fry... there are a lot of other mouths and the typical time to spit them all out is early in the morning (when I'm not typically up), and turning off some of the circulation pumps the night before would mean pretty reduced flow until I could turn them back on.

I think my plan for the next time is to catch him around day 15 and keep him in the box as before.  If the eggs disappear the next day, it will be clear that he's eating them, but the hope is that maybe as they're less developed he won't feel the immediate need to and will be able to settle into the box a bit better (hopefully?).  I could also try transferring him to a different tank, but unless the size/exposure of the mesh box is the thing bothering him and not the physical transfer, I'd expect it to have no effect.

I've also got PE Calanus back in the frozen food rotation, in case something about my feeding was nutritionally inadequate, but I doubt it was - I've always fed heavily and with several kinds of food they like.

[Steve G]

Hi, I've been following this topic with some interest as I had a pair of banggais spawn in my tank. In fact, I was not trying to do this, but one day I came home from a trip and found two fry in my overflow. My overflow is large, about 15 gallons, with complicated plumbing that made it really difficult to get them out, so I left them there for a couple of months, feeding them directly.

 

Over the first two months, they were growing, but only one survived. Then one day he made it down to my sump, where he's been living for the past month or so in the first chamber. It would be easy for me to net him out, but I don't want to put him in the display and I don't feel like setting up a separate tank. I could, and probably should, but haven't gotten around to it. I was thinking maybe I'd sell him to someone who wants a single banggai. I fear that introducing him back to the tank might be a death sentence as all my fish are pretty well established and territorial. Only one of its parents is still alive. Any suggestions?

[DaJMasta]

It's possible it could survive if the tank is large enough and/or the remaining parent is the opposite sex, but I wouldn't try to move it to the display until it's, at minimum, an inch and a half long, which probably is 6-10 months of growth.

 

Otherwise I don't think you'd find too much trouble rehoming it, especially for people with smaller tanks or with concerns about them being aggressive to each other, one is an appealing quantity.

[DaJMasta]

A little update without much more success, but an interesting development, I think.

The pair spawned about 2.5 weeks ago (forgot to write down what day, but I think Sunday was 15-17 days post spawn), and since I wanted to catch him early, I put the trap in on Saturday.  I saw them hanging around in it on Sunday, missed my first chance, and then saw him spit out two (maybe three), so I shut off the pumps and managed to get two caught with a baster.  They went straight down to the substrate and towards a hole in the sand after spit out, and were both alive, but that probably explains where they have been going if he's been spitting them out early.  I put them in a mesh box, then managed to catch him a bit later (with a less full looking mouth, but I didn't see him spit any).

 

By the end of the day there were 10 or a dozen in the box, a number of which were alive (at least at some point), and he started eating at night, so I let him out.

The ones spit out were all noticeably premature - one was an egg, the others had hatched but were basically a tadpole with a yolk sack (no forking of the tail yet, very little swimming), and it almost seemed as if the yolk could twist at its connection with the body of the fry - probably a very risky thing being outside of their parents' mouth at this point.  It also could be that they were not developed enough to pump water over their own gills well, so I don't know how well they could have survived under best case conditions, but the following morning none of them were still living.

So they're being fertilized, and they're developing, but it sort of seems like they're being spit out early, and being lost in the process.  I don't know what I can do, exactly, and I don't know why he's spitting them out.  It could have something to do with my catching him and them sort of remembering and getting agitated from it, but that could be beyond what they readily remember/understand.  It could also be some nutrient related thing, but I don't really expect it to be as their diet is still varied and they still eat a lot.  There is some chance they're being effected by some environmental factor - I recently found that my refractometer was drifting low and quickly, so I've been under salinity (~32ppt) for a bit now - but I don't know if that would have a significant effect on them.

I think I will try the same next spawn cycle, just trying to catch him early and have him spit them out in a mesh box, but maybe I'll try to sort of make an egg tumbler sort of thing - not likely to work well if their connection to their yolk sack is narrow and twistable, but if they just need circulation to keep alive until they can swim themselves, it should do the trick.

I know there are seasonal differences in spawn success as well, but as the seasonal changes in the tank aren't huge and the time since the last good spawn is long, so I think it's past that window for a fish that spawns pretty much every month.

Time will tell, hopefully.