Goldfish being aggressive

[ewan]

My neighbours pond goldfish have been bullying the other fish to death the water parameters are all good. I was wondering if anyone else has had experience with aggressive goldfish and why they're being aggressive also how to solve the problem.

 

[jlk]

My neighbours pond goldfish have been bullying the other fish to death the water parameters are all good. I was wondering if anyone else has had experience with aggressive goldfish and why they're being aggressive also how to solve the problem.

Do you know anything about the pond? Parameters? Size (gallons)? Number of fish? Types of fish?

The biggest reason for aggression that results in demise is simply lack of sufficient space. A 'general' pond stocking rule is 10g of water per inch of fish. For a pond with tons of surface area, some may go as low as 5g per inch of fish (after the first 50-100g) but even using this minimal rate, a 5-6in goldfish still needs 30g to himself (and soon double this or more).

If the fish are large adults, the aggression may be the result of breeding activities but this rarely results in multiple deaths-occasionally a single female may be bullied to death by males but its not very common in pond fish. More exotic fancy breeds of goldfish may incur higher numbers of injuries/demise during breeding activities though.

Some more information will help us to help you better!

 

[ewan]

Other fish in the pond include koi carp, tench for some reason they had a barbel one died from being bullied and they got another one,I told them not to get barbel but still, rudd and other goldfish.the goldfish killed a barbel and have been bullying one of the koi carp (almost died from what they told me). They are not sexual mature yet they are still around 3 inches only one goldfish is big enough he is the main bully which isn't surprising . The pond is 6000gallons.
I don't know the water parameters by number but my neighbours had them tested and said they were fine to me. This is not a thread about my pond to clarify.

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[ewan]

I don't know how many fish are in the pond.

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