You know what I think of when I think of a desert? Hot. Dry. In terms of animals I picture some lizards, rodents, maybe a fox or two. You know what I don’t think of? Fish. Fish in the desert? But there’s no water in the desert. So there’s no fish, right? Wrong. Apparently some fish do live in the desert, in desert lakes or tiny brackish pools that somehow stick around all year.

The masters of this lifestyle are the pupfish, which are known for living in very unpleasant and isolated environments. Hence, deserts. There are many different types of pupfish, most of which live in distinct environments. They comprise the family Cyprinodontidae, and there are 120 species. I couldn’t find one single species to focus on, so I’ll just highlight some of the more interesting ones I stumbled across.

Devil’s Hole Pupfish, Cyprinodon diabolis. Males are bright blue and quite pretty. By Olin Feuerbacher / USFWS – Public Domain

Firstly, there’s the desert pupfish. It lives, as the name implies, in the desert. More specifically, the only natural populations live around the Salton Sea in California and in Sonora, Mexico. Like all pupfish, they are small fish, only reaching three inches in length. They can tolerate waters with low oxygen, high salt content and high temperatures, which protects them somewhat from invasive fish that are unable to flourish in such environments. These conditions are harsher than that of almost every other freshwater fish. But mostly I like these guys because their name is the desert pupfish, which to me sounds a lot like an oxymoron.

Another well-named pupfish is the Devils Hole pupfish. They live in the Devils Hole Pool, in Nevada. The Devils Hole is a 2.5 by 3.5 meter cave pool. At least, that’s how big the opening is. It branches out a bit under the ground. The Devils Hole pupfish lives in the upper part of the 30 degree water, where they can find food. These fish are very lively, which is characteristic of many pupfish. This behaviour actually has lead to the name pupfish, as the behaviour of males during mating looks like puppies playing. The Devils Hole pupfish is one of the most isolated species in the world, and is considered one of the world’s rarest fish.

The Leon Springs pupfish is a hardy survivor of some terrible circumstances. It lived in Leon springs, which was subsequently impounded with a dam, then poisoned, then stocked with game fish and then drained. Talk about overkill. Anyway, this was in 1938 and it was assumed the Leon Springs pupfish was extinct. Alas, this fish is one tough customer, and managed to survive. It was rediscovered in the Diamond Y Spring near Leon Springs in 1960.

Pupfish have got to be some of the toughest fish in the world. Unfortunately, they live in such small and specific environments that most of them are critically endangered. Still, I feel like they’ll stick around, if only because they have shown such resilience in the past.

Cover image By P.V. Loiselle – Correspondence/personal work of P.V. Loiselle, CC BY-SA 3.0