I have lost three fish in four days
My NH3 is around .6
NO2 has been .3 - .5
NO3 floating around 35-45
PH is a fairly constant 7

Water is very clear and have two large air-stones going 24/7
They have been in the water for a little over a month with no problems up to now.

Red tilapia is the type of fish and I am completely baffled. The gills look clean and healthy and the only noticeable mark is a slightly darker red. one was under the jaw and another a small red spot of the face.

I read something in an SRAC publication that leads me to believe it may be a bacteria infection and needs to be treated with copper sulfate.

Has anyone else encountered similar problems? Any insight would be greatly appreciated.

Thanks to everyone

sanford