My son has a new aquarium.We are getting ready to start over because the fish got ich and died.He definately wants channel catfish.He also wants a gar.Will these fish be all right together since they are both predators?What other fish might be allright with these?One more question should I get a test fish first to see if I have got rid of the Ich?I've treated the tank twice since the fish kill.......Thank you Joe