I have a tank with african ciclids and one of them struggles to swim. Recently moving the tank so water change of roughly 40% happened. Before the move the fish liked to stay more or less immobile behind a plastic plant and often head down. Today he is just having a hard time swimming around. I looked into Swim Bladder disease which could be the problem. Any ideas on what is going on and treatment would be helpful. 75 gallon tank with around 20 fish.