Hi,

Recently, my 3rd feeder goldfish had died and I noticed it had black spots on it's fins, now, my 2nd feeder goldfish has black spots on it's fins too and the black spots seem to get bigger. Whats wrong with them and why did my 3rd one die?

The dark spots are probably ammonia burn. Change about 20% of the tank water asap to help reduce the ammonia if that is the problem. Next, keep testing the water and changing it until the ammonia level comes down.

How many fish do you have and how big is the tank?

Hi,

Thanks for they reply.

I HAD 3 feeders in a tank about 1 gal, since 1 died I now have 2 in there. If it is ammonia burn, wouldn't it affect all of the fish? Is there anything else I should do to help the fish?

Hi and welcome to Koko's. Hopefully you have read around the site and know that gf need at least 10 gals of water per fish. This is because they are very messy and produce alot of waste that turns into ammonia.

I would obviously recommend getting a larger tank, in this tank you will probably never get it cycled, therefore need to change 100% of the water every day. I know that is a pain but if you keep them in 1 gal that is what you will need to do.

To answer your question will it effect all the fish, yes it will in time.
I would change 100% immediately.
This site offers great information of how to keep fish healthy and happy.

Some things you will need in order to safely and happily keep the fish, is.....
1. a bigger tank.........at least 20 gals if keeping both. If they are commons, just feeder gf then they really need 20 gal each. Fancy gf need 10 gals.
2. a power filter that does 10x the filtration per hour.
3. tesing equip. for ammonia, nitrites, nitrates and PH.
4. if you have gravel you will need a gravel vacuum to siphon the gravel out once a week.

Let us know how else we can help you. Enjoy learning all about them, in the begining this hobby can be overwhelming but once your tank is cycled it gets alot easier.

Hi,

Thanks for the reply.

I'll try to get them a bigger tank very soon and I'll do water changes and test the ammonia.