Recently my Sterbai Cory has started looking very sick missing part of dorsal fin, he is swimming way slower than usual, his left gill is infected i think and his pectoral fin on that side has white stuff growing on it i think, his dorsal fin looks a little white on top too. I had 2 Sterbai Cories but the first died the day after i got it, not sure why looked completely healthy. There's a bulldog pleco and senegal bichir in the tank with him. His stomach also looks very pink. PLEASE HELP!!