I am new to this site but by no means new to fish care or oscars. Months ago almost lost all cichlids. Three survived, a convict, another cichlid and a plectomis. My eight year old oscar died tragicly almost over night. Still trying to find cause and correct. ph is 8.1, ammonia stays very low, nitrites are nearly untracable and nitrates stay around 40 ppm. 55 gal tank temp stays around 78-80. biological filter hangs off the back and overflows water back into tank topside. i use aquarium salt as directed, nutrilzers when adding water as directed, and slim coat as directed. thought i had seen and put my fish thru every disease and problem that could be had and learned alot over the years doing so. but this is beyond anything i've seen and noone has been able to help. i have tried everything and still introducing an oscar to this tank will kill them within the hour, so i tore the tank down, replaced the gravel, cleaned the ornamentals only leaving the biological filter intact. set the tank back up added the chlorine remover etc... next day added an oscar and hour later had to remove him from the tank and put him in another tank. i maintain my community tank the same way i do my cichlid tank, except for ph which runs higher from my cichlids. Oscar is recovering fine in this tank. they will act ok when i first put them in but with in a few minutes they will go to the bottom and litterly start to deteriate before your eyes. I add rosy barbs for surviving fish to eat. Sometimes takes days for these fish to get ate up but the barbs as well as these survivers are unharmed by whatever is killing oscars. any help, suggestions would be appreciated.
