My mom recently bought some fish for her 55 gallon 2 days ago. I was busy looking at some red devils and was not paying attention to her selection outside of preventing her from buying 2 kissing gouramis. I didn't like the look of the dwarf gourami from the very start. He had sunken sides and seemed fairly lethargic. He acted fine enough to not appear sick to my mom but something didn't sit right with me. I've finally convinced her something is wrong with the fish and to remove it. The poor gourami started to sink to the bottom and was getting more and more lethargic. What worried me was his sunken sides. We would eat but not aggressively. I've never experienced this sickness but I have done some research and would suspect something like wasting disease. Some people had entire tanks wiped out one by one by this and others never had another fish fall sick. Since I didn't see this sickness progress I have no clue as to what it actually is. Should I try my best to prevent the purchase of any new fish for a couple of weeks or is there a medicated food I can feed to them to prevent any more fish from contracting the problem? He was only in the tank for 2 days. Is this enough time for whatever he had to spread to the other fish? There's 3 guppies, a black moor goldfish, a tiny Chinese algae eater and a really mean black molly (again, I did not approve of the fish selection I just try and keep whatever they buy alive and healthy). I can't treat the whole take with my meds because those are reserved for emergencies with my wild bettas and I am not sure if I can prevent more fish from being bought. What would be the best course of action to spend as little as possible but keep these fish alive and healthy?
