How can I tell if my goldfish is being bullied?

Question

I was watching my goldfish swim around and one appeared to be chasing the other in circles. This did not last long and then they seemed to be relaxed and following each other and just swimming together. I am concerned, as if there is bullying, I will have to separate them.

What is healthy fish behavior, and what is a sign that there is bullying?

This is after asking this question here: Can goldfish bully each other after an injury?

Answer 1

Other than direct observation of the bully behaviour? Look for more general signs of distress or stress in your fish as bullying is a very stressful situation. Some common signs include:

1. Surface gasping (usually more about oxygen in the water, so unless only one is doing it, it's not a bullying thing, but watch for it anyways).
2. Fish doesn't eat. If the bullying pushes them away and they give up.
3. Hiding. The bullied fish hides and doesn't come out.
4. Visible injury or illness. May not be the result of bullying, may be the reason for it.
5. Swimming funny, which could be a consequence of injury from bullying.

The last two look a bit chicken and egg, so knowledge of the history of the fish in question are useful. In your case, you have reason to believe that one may have already been injured, so you're probably looking for other signs.