I have a 25 gallon freshwater tank with african cichlids. Fish included are 1 Red Zebra (4cm), 1 Aulonacara(7cm), 1 Pseudotropheus(4cm), 1 Kadango(10cm) and 1 Venustus(10cm). Then tank was setup 3 months ago with only the venustus and the zebra and were doing fine for 1 month. After that I added the other 3 fish and venustus started having signs of fin rot on the back fins. It was slowly but steadily deteriorating its fins. I treated the tank with Tetra General Tonic which i supposed to be good for fin rot, but did not improved its fins.
Two months after the initial steup I removed venustus in a 10 gallon hospital tank and following my LFS
suggestion I treated the fish with malachite green. Again...nothing happened. Venustus is still in the hospital tank alone and every day is getting worse with his fins (very very slowly).
My tank parameters both hospital and normal have 0 values for ammonia, nitrites and nitrates, 27 C and 7.9 ph
. I change 30% of water every 2 weeks (hospital tank is changed every 1 week).
Can you please give me any ideas of what is going on??
P.S. Side fins seem OK and not affected.