[color=blue]An irridescent shark would be a nice addition to your tank i think. It does get big, about 20 inches i think. I have one in my 55 gallon tank. Hes actually ok in there and about a foot long. I got him when he was a few inches smaller. Not much. Mine grows kind of slow and is in no way remotely close to being agressive. Hes about twice as big as the largest fish and occasionally gets picked on himself by something as small as a barb. Ive heard that a powerhead may be a good idea to give them a strong current to swim in but mine is fine without one. He just swims lazily around the tank. If your other fish are real aggressive i probably wouldnt reccomend it. I hope that answers your question.