Originally Posted by ellespencer
i feed them natural tropical fish flake 3-4 times a day, just a pinch and they have defrosted bloodworm maybe once twice a week. the water is fine i checked the amonia and nitrate the other day and they were both 0mg. none of the other fish look like this and this one was bloated slightly when i got it from the shop and seemed to be getting worse so it was already ill. can my other fish catch it and should i take it out the tank?
I am pretty sure your fish obtained the illness 'dropsy' from your LFS. It is caused by improper diet, temperature fluctuation, bad water conditions and overcrowding, as well as no real known cause is some instances. It can also be accompanied by Pop-Eye, which your fish may have based from your 3rd pic they look kind of swollen.
It's a dangerous buildup of internal pressure, that can be caused from parasites among other things.
I would start treating with some meds and quarantine him from your other fish. Although, meds aren't a sure fire cure, as dropsy is a very tough disease for a fish to survive.