We have about 15 gold fish and one all white fish that is just a little larger than the gold fish in about a 1000 gal pond. The white fish maybe a Koi. The gold fish have been chasing and biting at the white fish non-stop for days. I don't know how the white fish has servived. Today they have chased him since I first noticed early this morning and they are still at it. Can any one tell me what is going on?