We have a saltwater fish tank at my office and I noticed one of our pajama cardinal fish is starting to act funny. He is moving in very quick, short movements and then he will rest at the bottom of the tank. We have about 7 other fish a cleaning shrimp and starfish and they are all acting fine. I had noticed our green chromis (sp) was acting funny and then it would hang at the top of the tank and eventually it died. I have asked the guy who comes in weekly to clean the tank what might have been going on and he said the green chromis was fine. I don't have much knowledge with these our fish but I am very attached and worried.