Tilapia fry fin rot?

[harryarmst]

I have a 75 gal tank with about 50 Blue Tilapia fry (1.5" to 3.5")in it. They have been in the tank for about 4 months. The water was getting pretty cloudy with a bunch of solids in the bottom so yesterday I did a complete water change. I pumped the old tank water into a different tank to hold the fish then cleaned out the tank and filled it with rain water. I then moved the fish back to the main tank. They started swimming at the top, gulping at air like they needed more oxygen. I started an additional bubbler and this morning they were swimming normally but most had a red spot on their gills. When I got home from work this evening, most of them have black on the end of their fins and the ends seem to be falling apart! The water tests at pH: 7.0, Amm: 0.5, Nitrite: 0, Nitrate 10. Can anyone give me some direction?

Thanks,
Harry - Orlando FL

[kellenw]

Hi Harry,

First off, welcome to APHQ! Glad to have you with us.

With regard to the tilapia issues, try administering a salt treatment. Add 1 tablespoon of sea salt or non-iodized table salt per 5 gallons.

[keith_r]

go with kellen on the salt.. it will help the fish..
if you don't have an air pump, get one and add it..don't feed for a few days, test water often

[Pugo]

Welcome to Aquaponic HQ!! You have received the best advice there is. Hope the fish recover if it is possible the salt will do the trick...

[ande]

Welcome Harry
Salt is fine for a acute threatment of various fish diaseses, but IMO you got to define the cause(s).
http://thegab.org/Illness-and-Treatm...h-my-fish.html
http://www.michigan.gov/dnr/0,4570,7...7391--,00.html

Maybe most important ?
http://edis.ifas.ufl.edu/fa005

chers

[harryarmst]

Thanks for the advice. I added a small amount of non-iodized salt and in two days they looked totally normal. I dont know if it was the salt or they adapted to the water change but it looked kind of like a miraculous recovery.

Harry

[kellenw]

Great to hear! Tilapia respond really well to salt treatments. They can handle much higher salinity than most freshwater fish.

[qommunity]

Looks like you got a bacteria bloom when you did a full water change.