hello im new to aquariums and i have barra at 20cm in freshwater ive lost one to unknown problem and my other seems to be sick,colour of fish appears to be fading as hes going pale ,sits on the bottom regularly or he is in the flow from the power head ,still eating at the moment from what i can tell,water tests all ok ,also have shrimp and perch in there and there ok and no problems the one that died in other tank had similar problem except had what looked like mucus all over including eyes any help would be appreciated
