FanTail gold fish died

Question
I live on a cattle ranch and have 6 water troughs with gold fish in them.  Two tanks have breeding pairs, and they are like rabbits.   I recently moved one to the tank of a breeding pair with in a few days the fantail  stared floating upside down and staying upside down at the surface of the tank.  I shouldn't have moved it.  I had 4 large ones and I worry that that there is to many in the tank.  I try to keep the larger ones 2 to a tank.  When they get to about 4 inches or bigger.  I keep spreading them out on the ranch water troughs.  I haven't had any die before.  I don't know if I did some thing wrong.  If the two breeders killed the new one.  They are all on the same water system.  So the water is the same in each tank.  Or, the water comes from the same water source.  I am sure each tank is a little different.  Did my fish die of natural causes.  Or did the other fish cause him harm?  I have had these fish 2 years now.  Plus their babies.  This would be like raising them in out side fish ponds.  Well I am sorry I didn't see the no pond questions.  Really I am just courious if the other fish killed the one that died  or if they become territorial/  donny  thank you

Answer
Hi Donny;

Poor guy. He may have died from shock. It is common when moving larger fish. They aren't as resilient as the younger ones. Be sure to acclimate them in a plastic bag like you do when you bring new fish home from the store. Take the fish from it's old home with the old water. Float it on the water in the new home for 10 or 15 minutes before releasing them. Also, mix a little water from the tank to the bag a couple of times during floating. This gets them acclimated slowly and helps avoid shock.

Goldfish really do like to breed in groups so I don't really think they killed him. Unless they were picking at him or chasing him?

Followups welcome

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Chris Robbins

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