Is My Goldfish Being Bullied?

by Sandra
(Ireland)

Hi.

So a few months ago I decided to get a normal goldfish (bastion) and he was quite happy and energetic. I put him in a 60 litre tank but he looked really alone so I decided to get 2 other fish. One is a medium sized black goldfish (junkrat) and a larger gold and white fish (zenyata). They all seemed to get along at first but the last few weeks now, I've noticed bastion sitting under the black filter just looking upwards. The other 2 swim around and are energetic.

I recently noticed that bastion isn't eating too much and seems to not go around the tank at all. Zenyata (the large gold and white) seems to chase both of the other fish. I'm not sure if he/she is trying to mate with the black one or just chases them in a mean way.

I've also noticed bastions tail being a little tattered and this was pretty sudden.

Is bastion (the little fish) being bullied by the bigger fish? I've no other tanks to separate him from them either. Should I just give the bigger fish away? I'm not a professional fish holder. I just really love goldfish and decided to get them as company for myself so I'm not sure of the behaviour of them.

Hope to get some help on this thanks.

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Grant's Reply


Hi Sandra

Goldfish don't normally bully each other, even when there are quite large size differences.

The larger fish will dominate the food at feeding time, but as long as you make sure Bastion is getting enough, that shouldn't be a problem.

You excellent observation of behavioural changes is the key to successful Goldfish keeping, and it makes diagnosis a lot easier.

You mentioned that Bastion was fine before and shortly after the new fish were introduced into the aquarium.

This leads me to suspect the two new fish have introduced a disease into the aquarium, I suspect parasites.

You will need to act quickly.

My guess is the parasites will be flukes. Fish under 2 inches in body length are susceptible. The other option is a protozoan parasite. Both are tiny and very hard to see. You may be able to see flukes on the black fish.

Go to the diseases pages about flukes and Costia. Both can be cured by a Praziquantel based medication.

Even though Praziquantel won't harm plants or filter operation, so can be used in a set up aquarium, I would still separate Bastion from the other two fish as Goldfish will pick at a fish weakened by disease. Use any container that holds 10-20 litres.

I would also include some un-iodised cooking salt in Bastion's water in case it's not parasites. It will take care of any bacterial problems caused by the parasites (which his tail is exhibiting).

Something else to consider is you have tripled the bio-load on the aquarium. I would purchase a water test kit to make sure the water quality is good as 60 litres for three Goldfish is a little small.

It sounds like Zenyata is a male in breeding condition. Males chase the female to get her to release eggs.