Rainbow Fish Fry

[voo]

Hi,
I've been rescaping my tank and so kept a lot of plants in a bin filled with water (unheated, but in the living room). About 2 weeks later my brother notices small fish swimming around the top.
 
We removed what fry we cound find (around 50) and started acclimatising them in my main tank, which they are now in, in a net.
 
I've been feeding liquifry and crushed flakes, although i've never seen them eat. They used to hang around the top of the water, but now they seem to be hiding in the bottom corners of the net. There also seems to be very few of them, although i can't find any bodies (they're small, but don't think they can get through the net?).
 
I've now noticed more fry swimming around the top of the unheated bin. Should i be catching them and putting them in the net too? They seem to be doing better in the bin 

 
Should i be doing anything different with the fry in the net? I've put a few plants/bits of moss in there but they're not swimming around much.
 
I'm also assuming they are Boesmani rainbow fry.
 
Thanks

 

[george4593]

hi,
the fry will die off through natural selection and other fry may eat them. I have rainbow fish fry at the moment, I had around 70 but I only have 15 now because of natural selection (I never saw bodies either) . if you want to keep the fry in the bin I would put a heater in and heat it up very slowly. they will be fine in the bin if you want to leave them, but if you keep them in the net make sure there is plenty of places they can hide.  I see my fry eat but they are a few weeks old now. I feed them on crushed flakes and a few drops of liquifry.
 
good luck

 

[voo]

Thanks, i'd rather keep them in the net as the water is already heated. I was just curious why they seem to be doing better in the bin, unless that's because they are newly born.
 
I have some more plants i can put in the net so i might so that and see how they get on.
 
thanks

 

[fluttermoth]

It's almost certainly to do with dilution of toxins in the larger volume of water.
 
Fry are very sensitive to ammonia and nitrite and, even in mesh breeder boxes as opposed to plastic ones, there isn't enough water movement through it to keep the water clean.
 
They'll do better in the net if you change the water in it at least twice a day.

 

[mikev]

Inappropriate food. Liquidfry is nearly useless and causes ammonia spikes, especially in small amounts of water. Crushed flake has two problems: it is difficult to crush it into sufficiently tiny segments unless you use mortar and pester, and flakes are low-quality food.
 
Use something like Sera Micron, followed by artemia once the fry is large enough, and you should be able to achieve nearly full survival.
 
Further, it is difficult (not impossible) to raise rainbow fry in anything less than 2.5g., Low level of water for a couple of weeks helps. Plants like moss or najas help.
 
hth