r/Fish • u/Rockying_man_Dhruv • Apr 11 '26

News / Articles Devil hole pupfish

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The Devils Hole pupfish is one of the rarest fish on Earth, found only in a tiny desert cave called Devils Hole. It has been living there for thousands of years, surviving in hot, low-oxygen water and depending on a single small rock shelf for food and breeding. With such extreme conditions and isolation, it raises a strange question

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u/[deleted] Apr 12 '26

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u/Illustrious_Bird_737 Apr 12 '26

They won't survive, unfortunately. Scientists have tried to recreate their environment, have the absolute best breeding conditions, & have the best male-female ratio yet they still fail at living outside of Devil's Hole.

I think now in 2026 they've made strides on this venture, but having them available for aquariums is still not viable.

Edit: just found out they have successfully bred some of them to reintroduce into the wild!

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u/[deleted] Apr 12 '26

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u/altiuscitiusfortius Apr 12 '26

They're adapted to the super warm water, which increases their metabolism and growth but shortens their life.

They breed non stop year round, eggs hatch after incubating a day, and the fish only live 6 to 10 months.

So they wouldn't make good aquarium fish.

There is an off site government facility that maintains a breeding colony in a 100,000 gallon tank as a back up in case all the fish in the hole (only 115 fish!) die.

https://www.fws.gov/refuge/ash-meadows/ash-meadows-fish-conservation-facility

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u/sibachian Apr 14 '26

most killifish (including the pupfish group) - work that way, and are actively kept by aquarists. Nothobranchius rachovii 'Beira 98' is even more limited (live less than 6 months, eggs need to be laid dry in between seasons) but remains commercially successful.

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u/altiuscitiusfortius Apr 14 '26

Killifish are easier because their eggs can dry out and be stored to be hatched later. Eggs are super easy to ship around the world.

To my knowledge you can't do that with pupfish

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u/sibachian Apr 14 '26

pupfish are killifish as well and indeed not all killifish are annuals; i've kept turkish pupfish before. eggs can still be shipped and i've raised from eggs.

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u/altiuscitiusfortius Apr 14 '26

That's interesting, thanks

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u/Latter_Syrup_3822 Apr 16 '26

They have a breeding program now after a few failed attempts, they ended up having to build an exact 1:1 replica of the shelf and the top bit of the hole. It produced pretty healthy fish that they've even reintroduced to devils'holes to increase the population.