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Today on Animal Fact Files, we're discussing upside down catfish. You can subscribe by clicking the right side up button below! Thank you shelly la tortuga for today's long awaited request. This is the species most commonly identified as the “upside down catfish”, however, there are many other catfish species that have acquired this name, as well. That’s because the upside down swimming behavior that has brought about such a name for this fish isn’t exclusive to one species - heck, it’s not even restricted to a single family! Upside down swimming, however, can be useful according to some hypothesized reasons. It may give these fish access to food that other species aren’t utilizing. While most other catfish species spend their time perusing the bottom of their habitats, upside down catfish are most frequently seen towards the top of the water column. Here they’ll consume floating bits of detritus, algae, seeds and other plant materials, insects larvae, and more. Hanging out towards the surface can also come in handy when water conditions aren’t favorable. We’ve previously discuss some fish species that are able to take gulps of air as a means of obtaining oxygen in otherwise oxygen deplete watery environments - upside down catfish can also employ a similar strategy. By doing so, they can more efficiently survive in environments where other catfish species may struggle or expend more energy.

Swimming upside down at the surface has brought about some changes in these fish, as well. Speaking specifically in regards to what is considered the upside down catfish, the pattern of coloration across their bodies has flipped. Countershading is present in many animals living in watery environments. Consider the bottlenose dolphin trying to catch prey. From above, her darker dorsal, or top, side blends in with the darker water below her and her lighter ventral, or bottom, side, blends in with the water lit from above. This helps to camouflage her against her environment, which can give her an advantage while trying to find fishy food. The same often works in reverse for the fish she hunts- helping them to avoid her predation. But what about the upside down catfish? Simple: they just swapped their countershading. Instead of being darker on top and lighter on bottom, upside down catfish are the opposite. This tactic likely aids them in avoiding predation themselves. Plus, being upside down, they likely have a decent view of the water below them, which might give them a chance to avoid hungry predators. Upside down catfish are usually only a few inches long so they make an easy meal for other larger fish as well as birds and fish eating mammals. Blending in can help keep them off the dinner menu; it doesn’t hurt that they’re more active at night, too.

The most well known upside down catfish are from tropical waters of eastern Africa, but, like we said, this trait isn’t unique to one species, and catfish living outside of Africa may display this topsy turvy behavior. How the upside down catfish specifically reproduces seems to be relatively unknown, though some accounts indicate that they breed after heavy rains- producing hundreds of eggs that hatch within a week and begin showing signs of upside down swimming by two months of age. Do you think you could live like an upside down catfish?

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