Is My Goldfish Being Bullied?

by Sandra


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.

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.

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May 20, 2018
Is My Goldfish Being Bullied?
by: Grant

If it's spring or early summer where you live, the energetic fish may be a male.
Look for white tubercles on the gill plates and the leading edges of the pectoral fins.
If the smaller fish is being harassed too much you may need to divide your tank.
Goldfish will also pick at sick fish, but I don't think this is the case, but look for signs of disease.

May 19, 2018
Is my goldfish being bullied
by: Anonymous

I have two fish in my 22 litre tank but my smallest fish has been hiding in a ornament lately and the biggest fish has been energetic and swimming around the tank. Also a few days I noticed the bigger one pecking at the smaller fish in the eye. What should I do ?

Sep 29, 2017

by: Grant

Hi Sandra

In a

Bastion would have been actively seeking out and eating eggs as the other two were spawning.

As you don't have room to raise fry, just let them breed, which they will do every few weeks in the breeding season.

Do a water change after spawning as it will be full of milt which will pollute the water.

Because Bastion has a tattered tail and is fairly inactive, he still needs to be medicated until his tail starts to heal.

Treat all the fish with Praziquantel to eliminate all types of parasites.

Sep 29, 2017
by: Sandra

Thanks for replying to my problem.

I asked my local pet shop for the medication but they had none available so I'll have to wait a day to treat him.

I did notice bastion come out from his little hiding spot and start swimming around now and the bigger fish has calmed down a bit. My local pet shop owner said the 2 larger fish may have been mating and bastion stayed out of it. Could that have been the explanation?

I'm still going to check all the fish individually for any signs of diseases and parasites like suggested.

If the 2 fish did mate, how would I go about that situation? I'm a complete amateur with goldfish and honestly didn't expect to have 3 of them. Should I just separate the 2 of them completely?

Thank you.

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