Goldfish

[langara]

Hi, 2 weeks ago we were given 14 goldfish for our pond, we already had a few small ones plus a Green Tench and a Koi Carp, all seemed to be going well until we noticed a few of the fish were harassing one of the fish, a rather large goldfish, who looked quite fat. We took it out and have kept it separate for 2 weeks, it seems to be swimming ok and also feeding well. We have spoken to the person we had the fish off and the said the same thing happened when they had the fish. Any ideas what is going on and is it safe to put it back in the big pond.

[Chipchopper]

It seems, the wrong time of the year for breeding being the problem but I suppose it could be a possibility.
I'm just thinking that if the pond is small, over-crowding may be the problem.

[Buenchico]

This isn't my area of expertise. (Let's face it, not much is!).

However this looks like it might be relevant here:
https://www.pets4homes.co.uk/pet-advice/why-is-my-goldfish-bullying-his-tank-mates.html

[AuntLydia]

How big is your pond? length/width/depth? Its it well planted, do you have filtration system? Finally how big are the goldfish you have recently put in (in inches approx.) ?