I have a question because im very confused, I have had a neon goby for about 3months that has been perfectly happy. I was feeding the fish yesterday and he was his normal happy self then today I saw him in a hole breathing very hard and now its dead. I recently added two harlequin shrimp and a six line wrasse. I had a bubble tip anemone, 2 false percs, and a mandarin. What could have done this to him?