I received 100 tilapia fingerlings on July 1st and have been losing one per day, every day, with a few ups and downs (I'm down to probably 30 to 40 fish now). The fish were all less than one inch long when I received them (although now some are as long as 3 inches while some are still else than an inch). For the most part, the fish all looked perfectly healthy to me at the time of their death. Some were bloated, some had slightly cloudy eyes, and some had been partially cannibalized.
I have all the following parameters within recommended ranges:
Ph (7.5 - 7.8)
DO (2 - 5 mg/L)
Tank Size (250 gallon)
Feeding (crushed small pellets from tilapia company)
Ammonia (as close to zero as I can read from the test kit)
I recognize that there could be some bullying, but I don't see the signs I would expect to see, such as mangled skin, fins and tails.
Parasites? Streptococcus? Any advice will be most welcome.