One Fish, Two Fish, Bird-Eating Fish, Glowing Fish

By Joelle Renstrom | Published

The African tigerfish freaks me out more than I think a real tiger would. At least a tiger could, in sleep, appear kind of cuddly (maybe), but this South African piranha-like fish looks like a prehistoric torture device. The clip above showcases its ferocity, especially when it comes to these teeth working together to bring down much bigger land animals — maybe that’s where it got its name? Tigerfish can grow up to 22 pounds, but despite that mass they can really turn on the jets, going up to 30 mph to swallow their unsuspecting prey whole.

A recently published study in the Journal of Fish Biology notes the first observations of the tigerfish eating barn swallows. That’s right — these sea creatures can actually catch flying ones. As of now, they’re the only freshwater fish who catch and eat birds. Check out the clip below to see it, but look carefully — it’s over in less than a second. That bird never knew what was coming. Hopefully one of the bird’s flock saw and has alerted the rest of the gang that they’re all officially winged bait.

The next group of fish is a bit more trippy and far less scary. Researchers have just completed a study of biofluorescent — glowing — fish, and have found more than 180 species that would make the guest list of any underwater rave. They found biofluorescence to be much more common than initially thought and believe that the glowing lights might allow the fish to communicate with one another. And maybe with sheep.

glowing fish

Glowing fish contain proteins that absorb and then produce light at a longer wavelength, which generates the colors. It’s the proteins that researchers realized are more numerous than they thought in fish, as the proteins dictate the color of the re-emitted light. Identifying and isolating the proteins could have practical medical applications. For example, a jellyfish’s fluorescent green-generating protein has been used in biological imaging.

The glowing colors of the fish are often undetectable by human eyes, so the researchers took blue lights with yellow filters underwater with them to get a full look at the fish. Researchers believe that the fish have similar filters built into their eyes so they can see one another, and that their color patterns may be specific to their species and help with mating, as well as camouflage. It also appears that the ability to glow has been enhanced via evolution over time. That makes sense to me — glowing different colors would definitely seem to indicate evolution. Maybe that’s why aliens always glow?