New Shubunkin

Question
Hi,
I've had two shubunkins for a week or so, but as their tank is big enough to accomodate another one I bought one the other day. (I honestly have a massive tank - and I know how much space they each need - so it's not a spacial issue.) However the new fish has sustained a few injuries on the dorsal fin, which look like tears and I am concerned that they have been caused by one of the other fish. I've been watching them today and it doesn't seem that the other two fish are bothering the new one at all (infact they pretty much ignore the new fish) and they allow it to eat the food. Was it just asserting some kind of authority on the first day or is it something that is likely to develop into something more serious and endanger my new shubunkin?
Kind Regards,
Helen

Answer
Hi Helen:  As long as the new fish is eating things should be ok.  He may have had an injury from being netted or when he was first released into your tank.  Goldfish are feeder fish in that most everything else except guppies will try to eat them.  When they are put into new environments they tend to get pretty stressed out until they figure out there is nothing in there that is going to eat them.  Most of this is instinctual for them and the best way to get them over the bump is to feed them.  My general answer to everything is brine shrimp... because it does so many things for fish on so many different levels... So try them on some brine shrimp and I think his fins will regenerate nicely.  The Brine in this case will provide him with extra protein and other amino acids to help with fin regeneration.  It will also keep the other fish preoccupied and satiated if there is an aggression issue in the tank it will likely stop when everyone tummy is full.  If you are feeding pellet food it will help all three fish to digest the pellets and help to prevent intestinal blockages.  Keep me posted... dave