The ocean is full of some of the most weird and wonderful creatures Earth has to offer, from the cutie patootie that is the dumbo octopus to the horrifying deep-sea football of your nightmares. While whales might be busy creating Fibonnaci spirals, one diver was lucky enough to see a larval form of a tripod fish that doesn’t even look real.
Frida Yolotzin, a scuba diving instructor, saw the fish while diving at a blackwater site off the coast of Cozumel in Mexico. Blackwater diving occurs at night and divers can be tethered to their boat with hundreds of meters of dark open ocean around them.
Yolotzin was fortunate to spot the larval form of a tripod fish while enjoying her dive. She shared the video of the fish on her Instagram profile writing that “a colorful reflection caught my eye, it was this extraordinarily beautiful fish swimming up and reflecting our lights in such a surreal way, being by far the most precious animal I’ve ever seen.”
Yolotzin also identified the fish as a rainbow tripod fish larva. Adult tripod fish, also known as spiderfishes (Bathypterois spp), are some of the world’s deepest-living fish found in waters around 1 kilometer to over 6 kilometers (0.6 to 4 miles) in depth. The name tripod fish comes from the very long pelvic and caudal fin rays, which can be up to a meter (3 feet) long, that they use to support themselves on the bottom of the ocean, according to the Australian Museum.
The tripod helps the fish “stand” above the seafloor and wait for their prey, typically tiny prawns and crustaceans, to come past and into their waiting mouths. Tripod fish are generally blind or eyeless, having little need for light reception in the dark depths of the ocean. Instead, writes Bec Crew for Australian Geographic, they feel the vibrations of movement through those long fins, helping them hunt.
Smithsonian Magazine mentions that the larvae have large rounded fins, as seen in the video, to help them mimic jellyfish and avoid other predators. The larvae are more often seen by divers because they are moved up to the surface by the currents. This is a strategy known as ontogenetic vertical migration, whereby as the larvae age they will migrate down into the deeper ocean, eventually reaching the sea floor.
“Probably we will be the only humans it will ever meet,” concluded Yolotzin.