3d Printed Pelagic Larva and Egg Collector

[DaJMasta]

I've been iterating on making a larval collector for a few months now and have something I think works well that I'd like to share. This collector should be good for gently collecting larvae and eggs spawned in your display tank or another situation where capturing everything out of the overflow or isolating the larvae from the other creatures isn't really feasible.

The complete set of models for the parts is available on thingiverse: https://www.thingiverse.com/thing:6168731

A rundown of the parts and how to actually use it is here:

And some notes and some extra clarification is available on my local club's thread, here: https://wamas.org/forums/topic/102446-3d-printed-pelagic-larva-and-egg-collector/

Total print time is fairly lengthy, and expect to use the better part of a kilogram of filament, with some additional assembly required, but the result is a reliable modular collection tool that is pretty easy to use.

 

[Kasrift]

I've been iterating on making a larval collector for a few months now and have something I think works well that I'd like to share. This collector should be good for gently collecting larvae and eggs spawned in your display tank or another situation where capturing everything out of the overflow or isolating the larvae from the other creatures isn't really feasible.

The complete set of models for the parts is available on thingiverse: https://www.thingiverse.com/thing:6168731

A rundown of the parts and how to actually use it is here:

And some notes and some extra clarification is available on my local club's thread, here: https://wamas.org/forums/topic/102446-3d-printed-pelagic-larva-and-egg-collector/

Total print time is fairly lengthy, and expect to use the better part of a kilogram of filament, with some additional assembly required, but the result is a reliable modular collection tool that is pretty easy to use.

Following because this is cool!

 

[K1utch]

Hmm very interesting Idea really want to see where this leads. Need to see it in action!

 

[DaJMasta]

The youtube video in the first post shows its setup, the actual in-action isn't all that impressive because you basically just let it run in the tank for half an hour or whatever without the pumps on. It will start catching as soon as they start hatching, but I've taken to getting a small cup and scooping up some manually and pouring them into the holding vessel - my nocturnal cardinals will eat up larvae and even eggs pretty fast if given to opportunity, so doing some manually helps get more harvested. The flow through the airlift pump has been enough to keep my ~45G tank adequately oxygenated at night seemingly indefinitely - I've had it run a few hours with the pumps off to no ill effect whereas I get maybe 1:15 worth before I see panting from the fish without any flow.

 

[K1utch]

The youtube video in the first post shows its setup, the actual in-action isn't all that impressive because you basically just let it run in the tank for half an hour or whatever without the pumps on. It will start catching as soon as they start hatching, but I've taken to getting a small cup and scooping up some manually and pouring them into the holding vessel - my nocturnal cardinals will eat up larvae and even eggs pretty fast if given to opportunity, so doing some manually helps get more harvested. The flow through the airlift pump has been enough to keep my ~45G tank adequately oxygenated at night seemingly indefinitely - I've had it run a few hours with the pumps off to no ill effect whereas I get maybe 1:15 worth before I see panting from the fish without any flow.

I just meant when you collect some eggs seems pretty cool.

 

[AstroMelly]

Cool project. Gonna give this a try.

Our clowns have been laying every 2 weeks for a few months now and we just set up a 22 litre tank as a fry tank. Eggs are due to hatch tonight but she is always laying on the glass at the moment so we cannot transfer and will have to try and collect the larvae.

We have tried putting a discus laying cone in their corner but she is having none of it so far. I’ve got a 3D printer and just bought a new spool of PETG so I will definitely be printing this and will let you know how it goes! Will probably be the next batch as I reckon this would be a 2-3 day print.

 

[DaJMasta]

It does take a bit because the parts are large, I have been using 200 micron layer heights, but you could try 250 micron (or more, especially with a nozzle larger than 0.4mm), the only tricky part should be the M10 threads for the thumbscrews.

If you can have the pumps off when you expect them to hatch and especially if the larvae are phototactic, I would guess this would do a reasonable job. While it should be fairly gentle in collection, I haven't caught many fish larvae with it, which in my limited experience are somewhat more fragile than invertebrate larvae.

 

[AstroMelly]

I am printing this right now - did the tall pump last night and now printing the tall skimmer. Our clowns hatched a batch of eggs last night - as I said they insist on laying on the glass in the corner of our tank - we stayed up til 4AM but only managed to see one swimmer just before 2AM then nothing! We managed to rescue him - 3 hours after we went to bed I woke up (7:30 AM) and all eggs (loads - maybe 200 more were left when we went to bed) had hatched but no larvae to be seen - anywhere. We have 6 banggai cardinals and I think they had a feast. Like you said they are actively hunting at night. Seems funny we saw one at 2AM then nothing for the next 2 hours - I think they were waiting for us to go away with our torches! The little one is on his own in our 22 litre now - got some live rotifers and live phyto delivered today and I did see him pecking at them on the surface earlier. I put a comment on your thingiverse - looks like 2 of the model files might be duplicates?

Thanks for the hard work you put into this - I really appreciate you sharing!

 

[DaJMasta]

I had accidentally overwritten the magnet mount version and ended up uploading the duplicate, I reexported it and reuploaded it to the correct part (~900kB instead of 2MB).

I'll probably have a new version of the rimless mount (maybe I'll call it something different) because I've tried it on a rimmed 10 gallon tank and while it fits, the ridge protruding on the inside means when it tightens down it's quite tilted. I can actually take some design elements from another model to make the change pretty quickly, but I do want to actually use it before it gets uploaded.

I've seen my cardinals going as far as hanging out next to shrimp that were spawning that night... and I think my mandarins now spawn behind the rockwork instead of out at the top for the same reason lol

 

[AstroMelly]

Heh - yeah we call our 6 cardinals The Bikers - partly because we cannot distinguish them well enough to name each one - and partly due to the way they chase each other in the evenings - and their black leather and chrome or course! They also like to hang around together staring people or things out (such as new coral perhaps) which is highly comical at times!

I'm glad we have not had any loss there as some people say they will chase each other to death. They were one of the first fish we added nearly 2 years ago. They have also spawned - I think we have 1, maybe 2 males - a couple of times at least - the first time I tried to separate the male at nearly the 20 day mark and he spat the eggs. Then second time I saw he had eggs and then appeared to have none but a few weeks later I saw a single fry in his mouth! At some point he released him into the display and just by chance I saw the young fish free swimming one evening. Since he was the only one he was able to get quite large in the male's mouth - maybe 8mm fin to fin. We did not know what to do so left him in the display but next morning he was gone. I found him in our filter roller - he had gone down the weir and we brought him on in a separate tank with TDO B size pellets, which he did appear to take. All was going well but after about 3 weeks he sadly perished. I think at some point he stopped eating - I was trying all sorts of prepared and frozen foods and he did not appear to be taking much of anything. It was so sad - we had been calling him Rodney.

Oh - and we found 2 more clown fry last night in the sump. God it was hard trying to suck them out with a baster/thin long feeding pipette but eventually we managed and all 3 were still alive this morning in the 22l. The other 2 were much smaller and had the red yolk sac still whereas Artois has no yolk sac and is probably 5mm already!

I bought some live Rotifers (which are 200-300 per ml) and concentraed phytonplankton to feed them - the intention is to start a culture using a copapod kit which I used successfully abouyt a year or so ago. Here are the products I have bought:

250ml

Live Rotifers

Get premium live rotifers for your aquarium. Boost water quality, enhance fish health, and maintain a thriving ecosystem.

reefphyto.co.uk

100ml

Nannochloropsis Phytoplankton Mix

Boost your marine coral health with our Nannochloropsis Phytoplankton Mix. Maximize growth and vibrant colors with this premium blend.

reefphyto.co.uk

50ml (probably way too much)

Rotifer Feed Concentrate

Provide essential sustenance to your aquatic ecosystem with Rotifer Feed Concentrate. Enhance marine life health and vibrancy. Discover more!

reefphyto.co.uk

Right now I am 'feeding' the (3) fry the live rotifers from the 250ml culture I bought. I added about 10ml of this to the 22 litre Tuesday night/Wednesday AM when we caught Artois. I added 5ml more this morning. I alos added some of the phytoplankton (not the concentrate which is intended to bring the rotifers on) this morning before leaving for work.

We are novices to fry rearing but looking for all information we can - of course we have scoured YouTube and found much good info there but always looking for good advice as ever!

Specifically - how much rotifers to add and how often - this tank is brand new and so you could say sterile. We have a sponge air powered filter running and a heater. I 'matured' the sponge in the display sump for like 3-4 weeks - probably not enough to make much of a difference but it will have some bacterial load so hopefully fine for the first batch (of 3)! I saw a bunch of pods hitched in on the sponge so I guess that's a good thing.

I really should make this a separate thread as it seems I am hijacking yours! Perhaps I will continue in my tank/build thread.

Looking forward to using the 3D print - I hope the rimless piece will fit over our 19mm glass!!! I looked on Cura and it seems to be 20mm but if not I will modify the design as best I can and reprint (or print the other version that you have kindly uploaded and use magnets). The problem I find is finding fully reef safe magnets for the wet side - usually you have to buy some other product to get them. We have a few 2 little fishes magnetic feeding clips but would like some heavier duty ones - the glass thickness is a factor. I guess we can use the Mag Float glass cleaner at a pinch for one side!

 

[b1llvance]

This is an amazing project. My egg collector sucks to the point I just shut pumps off at night, wait on the eggs to float and take them out with a pipette. It takes forever. I can’t wait to use this.

 

[DaJMasta]

Another option for those not going the printing route: get a sieve with reasonably sized mesh (maybe 200-300 micron), then scoop the eggs up in a cup and pour the cup into the sieve. Basically the same idea but all manual, and something I'll still to to collect things faster (my banggais are quick to feast when things spawn, so doing some manually means collecting 2x or more.....

 

[AstroMelly]

Quick update - I have printed all the parts, assembled the kit and bought a Lumintop torch as you suggested - which is excellent to be honest. It was fairly easy but took a few days to print - the trickiest bit for me was glueing the mesh into the side of the collection basket. I kept glueing my fingers but I managed a half reasonable job which I think will do the trick. Our clowns have laid again like clockwork but this time they actually laid on the terracotta cone which we put in some weeks ago so we should be able to lift that out and into the 22 litre tank on hatch night! Murphy's law applies...

Our 1 fry (Artois) that we collected from the last batch is now on day 10 in the 22 litre and hanging in there. I am feeding a small amount of rotifers daily as well as some TDO chromaboost B1 pellets (tiny) which he generally seems to ignore. He seems to be eating the copepods which came over with the filter sponge from the main tank so I guess that's good news as well.

 

[DaJMasta]

While I haven't tried to raise clowns, my experience has always been that they are much more interested in live foods. I think the movement pattern is important for them to distinguish it from just particulate in the water column, so having something live to offer seems to be the right way to start things off, though transitioning them to a prepared food makes things easier as they continue to grow.

If you're using rotifers early on, I'd consider maybe hatching some brine shrimp nauplii - very easy to do and relatively easy to catch live foods being used by hatcheries for ages - and if you have the interest, also copepods. Copepods are supposed to have a better nutritional profile, so while I haven't found that they're always the easiest for fry to catch or universally accepted, getting some into a growing fry's diet is probably good for health, and a variety of foods at least seems like a good idea.

 

[b1llvance]

Not a clown thread but just an fyi, I begin my clown fry on tdo A at day 3 mixed with Rots and move completely away from rots by day 10. Start mixing in tdo B1 at day 6ish.

 

[DaJMasta]

Uploaded another file with a version of the Rimless mount that now fits rimmed 10G tanks, which is named "Larval Collector Rimmed Mount". It just supersedes the previous version, as it fits the same rimless tanks as before, just with a little more adjustment height and now also smaller rimmed tanks.