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Thanks to Nathan for his suggestions! This week we're going to learn about three strange and interesting fish!\n\nA northern snakehead:\n\n\n\nA giant snakehead:\n\n\n\nA Greenland shark, fish of mystery:\n\n\n\nThe upside-down catfish is indeed upside down a lot of the time (this is actually a picture of Synodontis nigriventris, closely related to the upside-down catfish we talk about in the episode):\n\n\n\nAn ancient Egyptian upside-down catfish pendant that ladies wore in their hair:\n\n\n\nShow transcript:\n\nWelcome to Strange Animals Podcast. I\u2019m your host, Kate Shaw.\n\nWe haven\u2019t done a fish episode in a while, so this week let\u2019s learn about three weird fish. Thanks to Nathan for suggesting the first two fish, the snakehead and the Greenland shark.\n\nThe snakehead is a freshwater fish that gets its name because while it\u2019s an ordinary-looking fish for the most part, it has a flattened head that looks a little bit like a snake\u2019s. Different species of snakehead look different in other ways, of course, so let\u2019s examine a couple of typical species.\n\nThe northern snakehead is native to Asia, but it\u2019s been introduced into other parts of the world by accident or as a food fish. It\u2019s one of the largest species, with reports of some specimens growing up to five feet long, or 1.5 meters. It\u2019s usually no more than three feet long, though, or 1 meter. It\u2019s brown with darker blotches and has sharp teeth that it uses to catch fish, frogs, and other small animals.\n\nLike other snakeheads, the northern snakehead can breathe air and survive out of water for several days as long as it stays damp. Young snakeheads can even wriggle considerable distances on land to find water. It likes stagnant or slow-moving water.\n\nBecause it\u2019s a fierce predator that can find its way to new waterways, introduced snakeheads are invasive species that can cause havoc to populations of native fish. The northern snakehead has been introduced into many waterways in the United States in the last twenty years, as a result of people releasing unwanted aquarium fish and accidental release of snakeheads in fish-farming operations. Since snakeheads reach mature age quickly and females can lay thousands of eggs at a time, snakeheads are illegal to own in many places now and release snakeheads into the wild is even more against the law.\n\nThe giant snakehead also grows up to five feet long, or 1.5 m, and is from parts of southeast Asia. Young giant snakeheads are red, but when they grow up they\u2019re black and white with a thick black stripe down each side. It\u2019s also been introduced into a lot of places as a food fish and a game fish, but since it\u2019s a tropical species it can\u2019t survive colder weather and isn\u2019t as invasive as a result, at least not outside of tropical and subtropical areas.\n\nThe giant snakehead can be aggressive, though, especially when it\u2019s guarding its nest. Both parents act as guards of the eggs and the newly hatched babies, which follow their mother around wherever she goes. That\u2019s actually really cute.\n\nNext let\u2019s talk about the Greenland shark. We covered it briefly in episode 74, about colossal squid and the things that eat them, but mostly we talked about its close relative the sleeper shark. The Greenland shark is similar in some ways but it\u2019s much bigger than the sleeper shark. It lives in the North Atlantic and Arctic Oceans where the water is barely warmer than the freezing point and it grows up to 24 feet long, or 7.3 meters, with females being larger than males.\n\nBut despite how enormous it is, it\u2019s not a shark you need to worry about. First of all, what are you doing swimming in water that cold? Second, the Greenland shark is a slow swimmer, no more than about 1 \xbd miles per hour, or 2.6 km/h. You can walk faster than that without even trying. You can probably dog-paddle faster than that.\n\nAnd yet, the Greenland shark manages to eat seals and fish and other animals that move quickly.