It is a 20 gallon
1 pictus cat, 2 weeks, shows no visible signs of any erosion
2 angelfish, 2 weeks, both have major erosion on fins, one on its side (these and the catfish were a present)
2 other angelfish, 4 months, one has slight erosion on its fins, other has no visible erosion
I have never seen the angelfish fighting at all, not even when I feed them, and all the fish are still active and eat (a lot)
I change approx. 4-5 gallons of water every 2 weeks(out of 20 gallons)
parameters:
nitrite-0
amonia-0
ph-between 7 and 9(i think)
cant test for nitrate or alkaline yet
I have also started to use melafix (bought the big bottle this time)