Kelly asked in PetsFish · 9 years ago

Do Killifish need heaters?

Do Killifish (My BFF fish) need heaters? And how much gallon tank do they need, because I heard they can grow up to 6".


JM, I guess the kind of fish that you can get in those my BFF packages. they look like they can only reach 2 and a half inches though.

Update 2:

so the fish are just gonna die after a year? ...

2 Answers

  • 9 years ago
    Favorite Answer

    Those kits are several species of what is call "annual killifish". These fish are called annual because in nature the fish die off each season when their wetland habitat dries up. The eggs are able to be handled and marketed like that for this reason as well, when the wetland dries up the eggs go dormant, waiting for the next wet season to hatch. So you get these egg kits where you "just add water instant fish" although it can be a little trickier than that.

    In the home aquarium, these fish live a little longer than the 9 or so months they live for in the wild, but about a year and a half is their limit.

    Yes, some killifish do get larger (some even over 8 inches), but not these which only get a few inches. (over 1,000 species of killifish, some are coldwater, some live in geothermal water!) For these annuals, if the room they are in does not have constant and stable temperature above 70F, get a heater.

    And only the males are pretty like that, females tend to be very bland.

    They actually do fine in smaller tanks of about 10 gallons. I know some breeders that use 5 gallon breeding tank with a peat moss substrate (to gather the eggs) per pair and that is an expert, but not uncommon, practice.

    Here is a good article on this type of killifish for further habitat setup and care requirements:

    Do some more research on "annual killifish" or Nothobranchius species.


    They might make it a few years with special care, but usually 1.5 years is pushing it on the annual species. Remember in the wild they hatch, grow, find a mate and reproduce in about 9 months before the wetlands dry out. They are easy to breed though once you get the basics down, so can have a tank with fish in it for many years, just several generations. There are non-annual killifish, some living a handful of years or more, but not in the kits.

  • JM
    Lv 5
    9 years ago

    yes they need a heater.

    what type of killifish? they vary in size.

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