Can a red tailed shark live outdoors with koi?

I have a young red tailed shark (about 3 inches) that I had been keeping in a 55 gallon tank. I thought he would be all right as the other fish were of similar size and different species, but he attacked one of them. The attacked fish is all right but I am trying to find a new home for my shark. I can't afford another tank right now but I have a large outdoor pond. I do want to put a few koi in it soon, so I am wondering if my shark can live with the koi. I have no idea if red tailed sharks will even do well outdoors, advice would be most welcome, thanks.