Surprised with a five-gallon aquarium...

[Colin_T]

IMHO, no fish belongs in a 5 gallon tank. It’s just too small of space. That’s just my opinion.

what about a male Betta splendens?

 

[PheonixKingZ]

what about a male Betta splendens?

I personally don't think Bettas should be kept in a 5 gallon tank, it's just too small of a space. An unpopular opinion for sure, but just from my experience, no fish belongs in a tank that small.

 

[Sgooosh]

That is correct

Heterandria formosa (Least Killifish)

The least killifish, Heterandria formosa, is a tiny livebearer from the United States, found in heavily vegetated margins of still or sluggish water. The smallest known livebearing fish, it is peaceful but not a community fish in the general sense, as the males reach only 2 cm and many commonly...

www.seriouslyfish.com

from what i know, they're just free food for gouramis

 

[Sgooosh]

I personally don't think Bettas should be kept in a 5 gallon tank, it's just too small of a space. An unpopular opinion for sure, but just from my experience, no fish belongs in a tank that small.

a grow out tank for a few fry could go well

 

[itiwhetu]

There are a lot of species that will readily spawn in a 5g tank. It is one of the standard sizes used in breeding rooms