How many fish for a ten gallon?

LordJoshaeus · 2026-10-15T11:32:02-0400

How many fish can I add to my ten gallon? Would a total of three 3 inch or less fish be ok once the tank is established? The only current fish is a yellow molly (not sure which species) named Curtis, who may or may not stay in this tank permanently. I was going to qt each subsequent fish -one fish at a time - in my 5 gallon qt tank for a month before adding them to the ten gallon. I really REALLY want an orchid dottyback for this ten gallon, likely as the last fish due to their temperament; I am unsure what fish #2 will be, but I am toying with a cardinal fish of some kind. Thanks :)

nautical_nathaniel · 2026-10-15T11:49:44-0400

Sorry to be the bearer of bad news, but neither of those fish would be suitable in a ten gallon. Some would probably debate on the cardinal but from what I've seen they do appreciate a bit more when they have it.

You will be very limited with a tank that size. My suggestion would be a Green Striped Goby, Blue Neon Goby, and/or a small watchman or prawn goby such as a Yasha or Wheeler's goby with a peppermint pistol shrimp. There are other fish out there that can be kept in a 10 gallon, but if you're just starting out those are the type of fish I would consider.

Now, if the dottyback is teeny tiny and aquacultured, I would say a 10 gallon is a good grow out tank. Some of the ones I've seen from ORA at a LFS have been like a half inch long and would get lost in a bigger tank haha

mfinn · 2026-10-15T12:36:14-0400

I would think more than 1 fish in a 10 gallon tank would be too many.

TikiGreg · 2026-10-15T12:43:46-0400

mfinn said:
I would think more than 1 fish in a 10 gallon tank would be too many.

he could do a few clown or gumdrop gobies.

Gumbies R Us · 2026-10-15T12:45:08-0400

1-2 fish is the most I would do. It really comes down to the fish you want to add.

I personally would avoid a dottyback in a tank that size. They are known for being aggressive (like you mentioned), and in a tank that small, it's going to be territorial.

LordJoshaeus · 2026-10-15T13:06:32-0400

If you can't keep fish in a ten gallon, what's the point in having one???

TikiGreg · 2026-10-15T13:09:57-0400

LordJoshaeus said:
If you can't keep fish in a ten gallon, what's the point in having one???

there isnt. 10g is more suited for small freshwater fish

Baldyreef · 2026-10-15T13:18:51-0400

mfinn said:
I would think more than 1 fish in a 10 gallon tank would be too many.

TikiGreg said:

there isnt. 10g is more suited for small freshwater fish

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I agree, in saltwater 10g tanks are usually kept as reef tanks with no fish or something small like a neon goby and sometimes a cleaner shrimp

Baldyreef · 2026-10-15T13:21:34-0400

TikiGreg said:
he could do a few clown or gumdrop gobies.

if you mean gumdrop coral croucher I highly don't recommend them, Ive kept them before and they are more cryptic then a possum wrasse the only time you'll ever see them Is late at night and they're spot feeding is tough because they push themselves into deep crevices in the rock where you cant see them, I would only really recommend them for someone who has established branching sps colonies so they wont be away all the time