gold fish fighting

Question
my three fish are budging each other one is a fantail with big eyes the other one is a normal fantail and the last one is a comet goldfish please help there killing each other ive already had to put one in a tank thats smaller because thats the only other spare tank i have but ive put him back because he was sad, there still killing each other its mostly the normal fan tail budging the other ones please help or they may die.

P.S i know there not breeding because there to young. there in a 14ltr tank.

Answer
Goldfish will chase each other quite often.  How big are they?  If they are over a few inches long, sometimes the males develop early and become frisky.  Comet goldfish are more apt to chase fish than the slower fantails.  I suspect your normal fantail might be male.  If they really are too young to want to breed, then it could be done out of boredom or for no reason at all.  Their tank isn't very big (not tiny either).  If you can put in more places for the fish to hide and give them more to do with things in the tank, that may distract them from pestering each other.  Sometimes separating one from the other for a while gets them to then behave better when put back together.  It can be hard to get goldfish to get along sometimes.  Good luck!

Robyn