I am looking for a species of fish that I could keep in a 10 gallon freshwater aquarium that will not spawn- either because I could easily keep all one sex or because the fish require special circumstances in order to spawn. I know that many fish, such as neon tetras, have a very high mortality rate for fry, but this is not quite what I am looking for- I want to avoid spawning in the first place. I cannot stomach the idea of fry dying in my tank.

Ideally, these fish would be shrimp-safe and schooling, but all suggestions are welcome!

Currently known fish:

Guppy; can keep all one sex, non-schooling, shrimp-safe
Betta; can keep all one sex, non-schooling, not shrimp-safe

  • A group of fish of one sex must not perform sequential hermaphroditism in which some (mostly marine) species change their sex (mostly from male to female). You might have some more trouble keeping a lot of males of certain species and having just 1 or 2 is most likely not your intention. Commented Jan 30, 2017 at 17:55
  • 2
    I find that putting your feelings about fry that you don't want above the fact that you basically want a fish that cannot reproduce in captivity, thus likely must be collected from the wild, is really selfish... Many tetra subspecies are completely sterile if they are not kept in very soft water, cardinals, rummynose, most neons, etc.. But I think you underestimate how hard it is to get any fish not in the guppy, platy, etc., or killifish, families, to reproduce in a small tank at all. It's unlikely to happen with any schooling fish in a 10 gallon tank unless conditions are absolutely perfect.
    – Jestep
    Commented Jan 30, 2017 at 21:17
  • @Jestep thank you both. I think you may be right about me overestimating fertility- I just read this on rasboras: "They must be kept in soft, acidic water with a temperature of 28C (82.5F) to have any hope of breeding."
    – jaynik
    Commented Jan 30, 2017 at 21:41
  • Both betta and guppy are hit or mist with shrimp compatibility. I currently have a betta in a shrimp tank and he leave them alone even more than the guppies I had
    – Rémi
    Commented Feb 3, 2017 at 15:19

1 Answer 1


Get guppies. They're pretty, readily available, cheap, and stay small enough to have several in a 10 gallon tank. The males have all the color, so you could just get males. Another option is to get multiple fish in either mail or female. Get some male guppies, male sword tails, some male or female platys or mollies. They're all easy to sex and stay small.

  • Another point about getting males - I once got a few female guppies from a pet store, but because they weren't kept separately, they had babies a few weeks later :(
    – user812786
    Commented Feb 2, 2017 at 14:20
  • Yeah, guppies are easy.
    – Dalton
    Commented Feb 3, 2017 at 15:13
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    I would not recommend guppies. With young fish it's often a bit difficult to identify their gender. Making one small mistake and accidentally having 1 male can result in 50 baby guppies a couple weeks later.
    – Diether
    Commented Apr 2, 2017 at 17:45
  • Typically, pet stores don't carry very young fish. It's also pretty easy to tell male from female guppies. Besides some results from new breeders, the females don't have color and the males have a lot of it. They start showing these colors fairly quickly. Unless they're buying fry, then I don't think it's an issue. You can also tell from the gonopodium, which shows up fairly quickly.
    – Dalton
    Commented Apr 3, 2017 at 19:55

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