Occasional Visitor

Black Goldfish

How many black goldfish can I have in a 20 gallon tank?
Community Manager

Re: Black Goldfish

Hi Ry,


Welcome to the community, I'm excited to hear you're interested in getting a black goldfish! However, since black moor fish (also know as the black goldfish) can grow to be between 4-10 inches, it's recommend to provide them with a minimum of 20-40 gallons. Here's a blog from the community with tips for how to help your goldfish thrive. It's always best to opt for a more expansive environment so they have ample room to enjoy. For more advice on which type of fish to have in your tank, you can call or stop by your local Petco and speak with one of our aquatic specialists. 


Alex Cat Very Happy

Esteemed Contributor

Re: Black Goldfish

I love Moor Goldfish. They are my favorite of all Goldfish. A twenty gallon tank will be okay for a single fish. As the other respondant mentioned, they get large and are better thought of as pond fish.  Ideally, a couple of adult Moor Goldfish should have a 40-55 gallon tank all to themselves.

They won't be lonely if kept one to a tank, and they will actually do much better than if they were crowded, in poorer water conditions and having to compete for food.

There are three "tricks" to keeping goldfish.  We;ve talked about the first one: SPACE, These are the other important issues

DIET: It sounds strange, but Goldfish don't do well eating nothing but dry flakes or pellets made for Goldfish.  They need lots of green food in their diet, or they suffer from swim bladder problems and digestive issues.  They should always have some Romaine, Spinach or sliced Zucchini to nibble on, and the dry food should be fed sparingly,

WATER: Goldfish are big and make a lot of waste, so it's necessary to do partially water changes on a weekly basis so that nitrates (fish wastes) don't accumulate.  See discussions of tank maintenance for a how-to.  If goldfish are kept in water with too much nitrate, you'll notice that there may be red veins in their tails and fins that clear up when water quality improves.  You won't be able to see this on the dark fins of Moors, but bad water wil affect them the same way.

Good luck with your fish.  Goldfish are high maintenance fish, but very rewarding because they can live many years -- twenty or more-- and become more impressive the larger they become.




“The oceans are the planet's last great living wilderness, man's only remaining frontier on Earth, and perhaps his last chance to prove himself a rational species.”
― John L. Culliney
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