Hello. I am very new to saltwater aquarium. It have only had fish in it for one month . My levels are normal when I test the water. It’s 76 degrees. I have no live rock, just fish. 55 gal tank. We introduced 3 Blue green Chromis then a month later we introduced 2 clownfish. I have the clown fish have been in the tank about 4 days. They were doing fine and eating/swimming normal until today. I noticed the small clown fish was in the corner of tank swimming very strange. And then the closer I looked I noticed it looked like it had a dark belly that I am sure was not dark when I got him. The bigger clown hasn’t been acting strange but today I noticed a small white pimple like bump near its eye. It’s slightly red around the edges. Does anyone have any insight? I’m clueless and googling the internet suggest a million different things. Thanks!