How do you stop breeding/excessive amounts of fish fry?

[ceruleanxstar]

So I adopted a praecox (dwarf neon) rainbowfish pair from a very kind SCAPE member here around a month ago. We didn't realize it, but they must have loved our tank so much they promptly started breeding. Nearly 2 weeks ago I panicked and thought that my tank had somehow developed mosquito larvae, only to take a closer look and realize that I had about a dozen fry. We got a mesh breeding tank, fry food, etc.

I read that the average # of eggs is around 30, so I wasn't too concerned. But we've accumulated probably 70+ fry and every single day we are still finding more. So far we've only lost maybe 10 fry (that I know of, maybe some got eaten or otherwise died before getting collected). We didn't do anything at all to encourage breeding but we did have a little heat wave that drove the tank temp up a good 5 degrees, but now it's back to normal. I did a bit of reading and assumed most fry aren't going to make it, but we're losing maybe 1 a day but gaining around 10!

I thought that new fry would stop hatching eventually but so far that hasn't happened yet.

So what do you guys do with all your fish fry? Also, do you discourage your pairs from breeding more? Should I just let any new fry stay out in the open tank and see if any survive? The SO doesn't have the heart to do this but I'm not sure what to do about so many fish babies. I've already bought and set up a separate tank to raise the fry once they get bigger (the biggest right now is about 1 cm), but I don't know how many are in the pipeline or how many I can realistically raise in the new tank.

[tippy4]

I had the same issue. Had a pair of Praecox Rainbows.....did a plant trim....dropped the plants in a tub with water.....a week later I see what I think are mosquito larvae....but keep watching and they're fish fry. I posted here asking what folks thought they were and the consensus was that they were praecox fry.

None of mine survived.

I tried dropping in baby brine shrimp but they never seemed to go for them.

Drop a pair of fish in the tank that will eat the excess fry.....circle of life and all that.

[kberg2498]

So I adopted a praecox (dwarf neon) rainbowfish pair from a very kind SCAPE member here around a month ago. We didn't realize it, but they must have loved our tank so much they promptly started breeding. Nearly 2 weeks ago I panicked and thought that my tank had somehow developed mosquito larvae, only to take a closer look and realize that I had about a dozen fry. We got a mesh breeding tank, fry food, etc.

I read that the average # of eggs is around 30, so I wasn't too concerned. But we've accumulated probably 70+ fry and every single day we are still finding more. So far we've only lost maybe 10 fry (that I know of, maybe some got eaten or otherwise died before getting collected). We didn't do anything at all to encourage breeding but we did have a little heat wave that drove the tank temp up a good 5 degrees, but now it's back to normal. I did a bit of reading and assumed most fry aren't going to make it, but we're losing maybe 1 a day but gaining around 10!

I thought that new fry would stop hatching eventually but so far that hasn't happened yet.

So what do you guys do with all your fish fry? Also, do you discourage your pairs from breeding more? Should I just let any new fry stay out in the open tank and see if any survive? The SO doesn't have the heart to do this but I'm not sure what to do about so many fish babies. I've already bought and set up a separate tank to raise the fry once they get bigger (the biggest right now is about 1 cm), but I don't know how many are in the pipeline or how many I can realistically raise in the new tank.

You cant stop them from breeding, but you can just give them bad odds of surviving and therefore you will have less. If you are over run you need more aggressive fish in your tank like maybe an angelfish or gourami which will eat em up. Rainbowfish will literally lay eggs almost every day. The reason they are expensive is raising those fish to sellable size takes nearly 6-7 months or more.

[jnunn]

My experience is that a jump in temperature will cause fish to breed. Check your tank temperature with a accurate thermometer and if its above 80 drop the temp down to 78. That should stop the breeding. As for the fry read up on the fishes breeding habits and set up a separate fry tank. Just for the challenge of breading them or let nature take its course.

Jim

[joethecinbeng]

ill buy some if youre willing to sell

[dwarph_shrimp]

I'd be willing to buy too

[ichthyogeek]

Agreed on buying some fish to munch on the excess fry larvae. Angelfish are a popular "fry eater" fish if I remember right.

[Speaker73]

I have a few dozen fry of southern red bellied dace fry myself. Need to get rid of them to. Lol

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[ceruleanxstar]

Thanks for the advice guys! We do only have six otos in the tank with the rainbowfish, so I guess that's why so many fry are surviving so well. Not sure if we'll add more egg/fry eating fish or what (the original plan for this tank was rummynose tetras lol) but good to know that's probably the best way to keep the fry population in check.

The water temp dropped back down to the usual 78F but dozens are still hatching daily. I do keep them in the open tank for a lot longer while now until I find time to catch and move them into the mesh breeding pen, so it's hard to tell if that's weeding out any weaker ones They sure zip around fast for how small they are and it's hard to working around all the plants.

We started cycling a separate fry tank already so we're planning on raising them until they at least get a little bigger, but I'll post an update for sure when we decide to sell/give away and I'll reach out to anyone interested. What size would be appropriate for that? The biggest are around 1cm right now and they're a little over 3 weeks old.

Edit: I still haven't figured out where she's even laying the eggs and I feel like I've stared at every inch of the aquarium by now Maybe in the rotala leaves near the water surface? Supposedly they lay eggs on fine leaved plants near the surface. We don't have any sort of mop like thing or even floating plants with trailing roots. What a mystery.