Skunk cleaner shrimp spawning log

[DaJMasta]

An update, hopefully with some improvements in the coming week.

 

The ones I collected at the last post lasted about 6 days, a similar track as before, though the quantity in the kreisel was lower, and since then, I've caught a few more various larvae (including my first captured sexy shrimp spawns, three on consecutive nights after moving them to the new rack!), but haven't had any success, always lasting a few days, starting to dwindle, and then eventually disappearing.

 

 

So I've identified a few potential places to improve and have set the wheels in motion.  I've got more apocyclops cultures going, but I've got parvocalanus in the mail again for a third attempt at culturing them - hopefully with better results after some more reading and some modifications to the culturing regime.  I've also read that in most cases of culturing organisms, multiple food sources outperform single food sources, provided each is usable.  I think the larvae I have can eat the apocyclops as I feed it to them, but it could be a little large for them (I think especially for the sexy shrimp) and there could be too many adults in the copepods fed to the early stage larvae, so while I haven't implemented it yet, I have plans on doing a two-stage sort by copepod size - probably with a 250um screen to remove the adults from the harvest to feed to the rest of the tank, while leaving the copepod nauplii and early stages to feed to the larvae.  I've read that many larvae will chase after any food they run into, but if it's too large, they expend the effort to try and catch it only to end up not or not being able to eat it.

 

While probably good for the long term results and growth speed going forward, I don't know if this alone will do a lot to get past the soft 1 week limit or so I seem to be running into.

Another avenue was to clean out the kreisels and then sand the inside to remove any burrs, layer lines, or other things that could help encourage debris build up.  Not a likely huge improvement, but maybe good for general cleanliness going forward.

 

Another still is trying to change the design of the kreisel.  While the ones I have I think can work, I wanted to try an upflow design (a lot of larval systems use airlifts, so the circulation is upwards), which could also be gentler on the larvae.  Yesterday I finalized a design for a D shaped kreisel container that has a built in spray bar to push water vertically along the flat side from the bottom, and I hope to try this design out in the coming couple of days.  Again, maybe not critical for solving my problem, but an improvement.

 

 

Then, I think, the most likely big improvement to the system: a UV sterilizer used in a very specific way.  I had been reading around about larval rearing systems and for a long time have noted that they are dedicated tanks, often not plumbed into a proper filtration system, that use highly filtered water as their input, and while the more generic benefits of keeping the procedure constant and better known as well as making sure parasites and disease doesn't get in is part of it, I think I found a critical role this plays in reading about seahorse rearing tanks: it keeps hydroids out.

 

I've seen hydroids in their pelagic medusa stage in the kreisels a few times, they are usually pretty easy to spot, and while I had seen at least one come over from the main tank, I've seen several more than just that one.  I've also noted that they disappeared after just a few days, and since they appeared fragile, I assumed they had died.  But according to the reason for starting from scratch in a seahorse rearing tank, these hydroids have practically their ideal environment in a larval tank with a huge amount of planktonic food, and that their sting was powerful enough to injure or kill small larvae.  On kreisels that had been running for a while, I was seeing some filamentous stuff on the sides that I had thought was algae or detrius, but which could easily be small colonial hydroids.  For a bit, I tried to concoct ways to start clean tanks to make some attempts, and while it still may be worthwhile, it involves more space, equipment, and effort than I really want to use, especially for regular spawns.

 

That's where the UV comes in.  The hydroids are already in the system and always will be, but since I'm using a pump fed design for the kreisels, why not filter the hydroids out to prevent (or lessen) them from getting in, and then the positive pressure of the water being forced in should help keep them from getting through the mesh in the side?  Well I had already been filtering the input to keep out amphipods (a 500um screen and a sponge to keep fry from getting sucked to it), but a significant enough dose of UV on the line from the pump to the kreisel (the pump just pulling from that middle level 10G tank in the system) should be able to stop a lot of problematic things from getting in, while still letting me rely on an established tank's filtration system.  So I've ordered a 18W UV (good in most circumstances for 100-250 gallon tanks) and will be running it at something like a tenth of its rated throughput to maximize the UV dosage and the chance that it will kill any hydroids in the water supply line to the kreisels.

 

I will yet have to see how well it works or if it has negative side effects, but I think this will likely be a big step forwards in keeping these larvae alive.  No idea for how much longer, but hopefully enough to get some big enough to not have to worry about any hydroids that develop in the kreisels later on in their development.

 

 

In any case, I think I've got another skunk cleaner that will spawn tomorrow night or the next day, and while I don't expect to have the UV in place by then, I should have a freshly cleaned kreisel in the new shape (and larger size) to start them off in and an ample supply of apocyclops.

[DaJMasta]

Yesterday I finished printing a second revision of the D shaped kreisel and the UV sterilizer arrived, so I set up everything planned and verified that it functioned at least on a basic level.  Then that night, I got the first skunk cleaner spawn in almost a month (both shrimp didn't carry eggs for one molt cycle, could have been normal but could have been a fluconazole treatment for algae around the same time).  While collecting this above average sized spawn, I collected a new type of mystery larvae - they look sort of flat vertically from above, but under the microscope they look distinctly like some kind of shrimp.  No idea what they are, I've now got three mystery larvae that could all match the mysid shrimp I have in the tanks, but none of which I can actually ID.  Hopefully they will live and I can find out!

 

The setup is wonky looking, but here's the setup earlier today:

 

Since they were clustering a bit on the back mesh, I printed up a light blocker for that side, and since installing they've all moved back to the central part (and it took less than a minute!)

The dark background is a bit better for video, and I've got a narrower angle lens now, so I took a short video of them swimming around, then got one of each in a pipette, put it on a slide, and took a look under the microscope.  The mystery shrimp especially looks interesting and fairly well developed, but as I mentioned... I don't have the slightest idea what I could be.

 

I see some debris (and even a little worm) in the video, so I will try to keep after cleaning things drifting around periodically, but the next week should give me a good idea of whether or not the UV will keep the hyrdoids out.  Their larvae are easy to spot (little clear jellyfish with white dots on them), and I didn't see any on collection and so far.

[howaboutme]

Thanks for the update! Love the ingenuity and your own engineering behind this endeavor. Keep up the good work.

[VA Reefdog]

Thanks for the info and updates.  Because of this thread-- decided to get a second cleaner shrimp to see what happens- just to see if I might get a spawn.

Amazed at all your work.  Kudos

 

[DaJMasta]

Glad to hear it!  My journey continues though my success is still limited.

 

I tried that batch with the UV on the input and they lasted about a week in total, more initially, then tapering off towards the end, so while I did see fewer medusa stage hydroids around and I think it's a benefit overall, it wasn't the magic bullet to get them to live longer.  I suspect it's nutrition related, but there is still more to try.

 

I've redone the plumbing to be a lot cleaner, using an inline valve after the pump to reduce flow, then a 3d printed manifold adapter to split the line evenly between three kreisels, and they both seem to work great (no concerns with leaking 3d printed plumbing bits when they're in the tank!)

I've had a couple more critters spawn and made attempts with the same equipment and am having similar results, though probably for varying reasons.  The more I read about breeding operations for other things, the more it seems like flow in the larval tank really doesn't seem to count for a lot, so I think with a future run of these guys and my next run of mandarins (my pair is spawning!), I'm going to just cut off flow to the kreisel they're added to, increasing it later on as they can swim better.  For now, the flow is much more uniform between the kreisels, and much lower.  While I haven't measured it, I'm powering the three kreisels from a single QuietOne 400 pump, which is nominally 100GPH, with an inline valve to restrict flow, so I'm estimating around 15-20gph per kreisel.... and it may be too high for some larvae, at least.  It's enough for visible movement in there, but only just, and very few larvae or debris particles can get pushed full circle around the edge.

 

My parvocalanus culture is to full volume, but the productivity seems very low, so while I will continue on and see if it slowly grows in, I'm also going to be reading up on some culturing techniques to see if there are some more details I can get out of it.  Otherwise, I've got a fair bit of production of apocyclops still, so I'm trying to keep the feeding levels fairly high, but I'm not totally sure the quantity is really sufficient either - it's difficult to gauge, maybe soon it will be time to start measuring success against quantity/frequency in a more structured way.

 

As for equipment modifications, I've got a front and back light blocker on every kreisel now, and I've slid the moonlights over each one to the right - I got the idea after watching the larvae cluster around the left top side of the kreisel.  I think having the light they're chasing being offset in the opposite direction of the flow (since flow comes up then goes counterclockwise in this design) should help keep them from bunching up in the corner as much.

 

Got another spawn last night (and got it on video, though in very low light), and caught a couple hundred and transferred them over.  This group will be getting more of the same treatment as before, but I'll add some TDO A and see if I can manage better than a week.

[akbuuur]

Oh man this is cool! If you’re able to raise them to adult hood I would definitely purchase some. 

[DaJMasta]

It's been a bit, and there was another spawn in between here that I tried to feed some artemia (mentioned in the mandarin thread), but I overfed the tank massively and they didn't last any longer than before.  An interesting thing from there: the larvae grabbed onto artemia eggs I had accidentally added in addition to the nauplii, and the method seems to be to use the longer forward arms to gather food towards some near-invisible legs directly under the yellow spot where they hold the food to eat it.

 

The spawn after that was really late at night - I saw the shrimp with eggs and there were a couple released, but after more than an hour and a half of waiting with the pumps off, I just turned them back on.  The next morning no eggs and a molt, so they just came really late.

 

Then last night was another spawn, I saw a few in the water and the banggais eating things so I put in the collector and left it on.... and the skunk cleaners weren't the only ones spawning, nor the most numerous ones collected:

 

The yellow/clear one is the familiar Lysmata amboinensis larvae, and the ones with the red are the related  Lysmata debelius (fire cleaner shrimp).  The spawn was not a huge one in total collected, and there are fewer skunks than fires, but I'm going to try co-culturing them in the same vessel, and I may be able to report some good results.  I had another fire cleaner shrimp spawn collected about a week and a few days ago, and with the equipment/methods from working with these guys, a couple of tweaks, and the artemia from trying to feed the mandarins... I'm seeing noticeably better results - about two dozen remaining after 9 days!

 

 

So what will be different for this combined run?
From the beginning and a few times a day, they will be fed artemia nauplii in addition to copepods (mixed size, apocyclops and tigriopus to start).  I also fed 50mL of chaetoceros diatoms a few hours after hatch.

The front and back light blockers will remain on except for viewing, and on the tank wall side, I've gone around the edge of the kreisel with a layer of painter's tape on the outside of the tank.  In the previous run, I found a few that tried to go after the little sliver of light getting through the tank wall around the light blocker (can't be made too wide or it blocks the magnets that hold the kreisel in place), so for the fire cleaner shrimp run and now this one, the extra bit of tape around the seam helps block out that sliver that can get in, and it seems to be effective.

 

 

Otherwise, I'm running slightly higher flow in the kreisels than before (but not a ton), and will be swapping to a new kreisel if I see any colony of hydroids forming - even with the sterilizer it seems to be inevitable.  As my new copepod cultures grow in, I hope to feed new copepods, and I won't be feeding artemia beyond a couple weeks old - I will probably be running out around then if nothing else, but would prefer transferring to renewable cultures of food.

Edited April 7, 2022 by DaJMasta

[lowsingle]

Following another thread if yours!

 

Darren

 

[DaJMasta]

It's been a little slow, and that's for a couple reasons, but I'll start with the bad news: I lost one of the pair a couple of weeks ago.

I don't know what exactly happened, but it could have just been old age.  I had been noting less frequent spawns in the last couple months, as well as occasionally missing spawns, and in the weeks leading up to its passing, I had noticed shorter whiskers and even algae on them(!), so it clearly was having some kind of molting trouble.  I woke up one morning one shrimp short but with the old molt on a powerhead (algae and all), so I presume something got it or otherwise something happened shortly after the molt.

Sad, but I don't think it was having noticeable trouble or suffered, and it was basically fully grown when I got it, so it may not have been young.  In any case, at the end of the last week I picked up another shrimp, it's been hanging out with the other one from the original pair, and it actually came in with some eggs (much smaller shrimp) that hatched out last night, so I have high hopes for more in the future.

Otherwise, I've developed and have been trying to refine a new kreisel design to try and fix several specific problems: air driven flow for simplicity and variability, a cone shaped bottom for easy cleaning while occupied, and a finer mesh to keep in smaller larvae (mandarins, for example) and to keep out hydroids.

 

This last mention was actually critical in using the last version, and one of the bigger reasons to try something else - I kept running into issues with hydroids.  Basically, while I had see no hydra stage hydroids swimming around after installing the UV, there was still fragments in the water when the kreisel was put in the tank (presumably), and with constant flow and food, they would always manage to grow.  I actually got the fire cleaner shrimp (closely related) to 18 days old using artemia as a food with the D kreisel design, but I ended up having to moving them at least 3 times in the course because of hydroid growth.  In an unrelated observation that converged into the new design - a lot of papers describing larval rearing involve minimal or no flow, so I've been toying with the idea of even lower or no flow rates.  This combines into the hydroid problem - if there's no flow in the vessel, it's harder for them to catch food, so they should at least grow slower - so moving to air driven flow gives more flexibility on the low side, while still having a mesh side to exchange some water passively and get rid of waste and control temperature.

Since the first design, there have been some revisions that bring it more in line with the last version  - rather than the pictured slats to encourage water exchange but block most light, I've just gone back to an internal light blocker as well as one for the outer glass.  I've tried a couple runs of things in them so far, but haven't found much success in the short term, though I'm also struggling to get my parvocalanus cultures to be consistent producers, so some of that may be the cause.

As things stand now, the smaller batch from the new shrimp is a day old, and since I had some losses with the air on low before, I'm trying no flow.  I still expect to have too little food for them as the parvo cultures are unstable, but I will feed them what I've got as well as some of the apocyclops and tigriopus cultures, so if I can get a lifespan comparable to previous kreisel's runs at least, I will know that for these guys no flow is a realistic option.

Otherwise, if there's something about the geometry of this cone design that's a problem, I may be able to convert the D design to an air driven version and give it a bit of a point on the bottom for easier cleaning, but I'll cross that hurdle when I come to it.  At the moment, I'm trying to print a second of the newest version, but for unknown reasons I've had the print fail in the last couple hours now three times in a row.... and with an almost 17 hour print, it's slow to try and reprint.

I hope to have some better information on how well the new design works as well as stabilized early food sources in the next few weeks, but I'll continue trying to raise up whatever these guys produce.

Edited May 10, 2022 by DaJMasta

[DaJMasta]

After the seemingly successful setup of the mandarins, I bought a second 10 gallon brute trashcan and a few low power heaters and filled it up.  A couple days ago was the full moon cycle of the lights, and tonight, I got a spawn of a skunk cleaner, then about 20-30 mins later, a spawn of a fire cleaner, so they will be by next run attempt!

 

 

Easily hundreds of each, so the density in the trashcan seems pretty high.  The plan is not to screen for copepod size and to focus on apocyclops with a small amount of tigriopus and tisbe added (the species I have available) and regular phytoplankton feedings, more to keep the copepods multiplying and nutritious than for anything to do with the larvae.

I have a single long light over the two trashcans now and I already see them gathering somewhat under it, while it may not be a problem, I may try moving the light higher to try to keep them from being disoriented (more uniform lighting, more of the light coming from a similar angle, etc.)

Let's see if simply moving to a big, sterile start container is the key to these guys too.

[YHSublime]

Freaking love this. The moon is looking real gorgeous tonight as well.