What's Wrong With My Fry?

[Man of fish]

I have about 20 fry in my 10 gallon fry tank with the smallest being about 1/3 of an inch and the largest being almost 3/4 of an inch. I usually do weekly water changes on this tank and double dose on seachem prime. Well last week I forgot to do my w/c, but the fry still seemed happy so I took my regular tests and got these results:
Ph-7.0
Ammonia- 0 ppm
Nitrite-0 ppm
Nitrate-about 5 ppm
So I did a 30% water change and the fish were ok. I raised the temp to about 79 since it was low at 76 1/2 (I don't think this is the source of the problem) then I left for the weekend so I left about 1 hour after my w/c yesterday and got back this afternoon. When I checked on the fry they all seemed happy and fine but I found one dead one. It was one of the two that were deformed in the batch so I thought nothing of it. Tonight I came in to find about half of the fry swimming as usual and about half hiding behind either the heater or filter. With this I did an emergency 50% water change and triple dosed on prime. I retested the water before this change and got
Ph- 6.8
Ammonia-.1 ppm
Nitrite- 0
Nitrate-0
Temp.- 79
So I did my 50% change and now the readings are
Ph- 7.1
Nitrite-0
Ammonia-0
Nitrate-0
What could be wrong with my fry???

Oh and they're platy fry and I have aquarium salt if that would benefit them. Also sorry for the story and thanks in advance.

 

[FishBlast]

A lot of fry from a batch die (usually due to birth defects). All my deformed ones died within a week from birth and from those that seemed normal, some others died until some survivors were left. But I didn't have a filter back then so not entirely sure on the ones with good aspect.

 

[Man of fish]

These are 4 months old

 

[JL94x4]

Pictures? Would like to see their colours etc, are they growing normally? etc?

Ive got 500 guppy fry in my 40 gallon tank (this is where all my fry grow up). Iv never really had a problem with guppy ry, 90% of them all turn out healthy and a good size, before i sell them on at 70p per fish to my local fish store.

 

[Man of fish]

I found maybe 4 or 5 with bent spines actually and it looked liked they were breathing heavy so I popped in an airstone. Yes they're all growing good I feed them on crushed flake and bbs. Sorry can't get a pic. One more died but he, also had a bent spine. There's still a couple with bent spines so must of been in the genes hopefully they'll get better with the stone.

 

[afremont]

I found maybe 4 or 5 with bent spines actually and it looked liked they were breathing heavy so I popped in an airstone. Yes they're all growing good I feed them on crushed flake and bbs. Sorry can't get a pic. One more died but he, also had a bent spine. There's still a couple with bent spines so must of been in the genes hopefully they'll get better with the stone.

Sorry to hear about the losses. Were these fish born with bent spines, or did they develop them?

 

[Man of fish]

I'm bot entirely sure I know that 2 were born with it but on the others I hadn't noticed it until today but they could've been born with them

 

[Man of fish]

I just noticed some of them have white stringy poop. Is this bad?

 

[Man of fish]

I found one with ich/ velvet I think. What should I do?

 

[Akasha72]

I was told recently that inter-breeding can cause fry to be born with bent spines and other deformaties. There's lots of info on here about weaknesses in certain breeds of fish due to in-breeding and over breeding. Could the parents of your fry be related?

Also, if there's signs of ich you could add some salt and up your temp or you could half dose with some meds. I've not tried the higher temp/salt route as I have cories but I have half dosed meds and found it to work. Waterlife protozin seems to be a good choice and was the one I used

Hope that might help

 

[Man of fish]

Ok I'll add the salt since they're platys and all. Not sure if the parents were related. I think they came from the same tank at petco I'm about to check on them now.

 

[Cazgar]

You do seem to have a lot of problems with ich & velvet, is this the 3rd time?
Try upping the temperature & adding the salt

 

[Man of fish]

Yes and I'm still unsure of what's causing it

 

[Cazgar]

How often do you do water changes & thorough gravel vaccing?
They also say ich rears it's ugly head when your fish are stressed.
Touch wood, I've never had it, & hope I never get it

 

[Man of fish]

I do weekly water changes and I do a regular gravel vac every week and a thorough one (remove all decor etc.) once a month. I'm not sure why they'd be stressed because they always seem perfectly healthy and the waters always perfect