i have a dalmation mollie.its clamped water parms fine and all the other fish are fine.no marks on him,seems to be roling onto his side and lying on the bottomany ideas?
It he looks like he is finding it difficult to maintain balance or he looks uncomfortable but there are no other signs, it could be an internal bacteria thing- there are some realy good meds by interpet for treating this.
Any other info you can give us would be useful too.
sounds like your fish has a swim bladder disorder if it is not swimming normally, they are usually caused by genetic problems/bacterial infections/bad water quality conditions but usually just internal bacterial infections in the fish...