Dusky kob making a fishy noise at the Two Oceans Aquarium

We usually don't think of fish as noisy animals - in fact, most people have no idea that fish make sounds at all. Two Oceans Aquarium Education Foundation teacher Kirshia recorded a very vocal display from the Aquarium's giant kob at night in the Save Our Seas Foundation Shark Exhibit:
Hear that drumming sound? That's the sound of kob signalling each other (the kob, a.k.a. kabeljou, are the smaller fish milling about at the bottom in the above video). Kob are members of a family of fish called "drums" or "croakers" that all possess special muscles that allow them to vibrate their gas-filled swim bladder and produce sounds. These sonic muscles literally drum against the swim bladder. Sound must be pretty useful for fish to have evolved this ability, so what is it used for?
In giant kob (Agyrosomus japonicus) only males have these specialised sonic muscles, and they are only used during spawning season, both as a way of attracting females and of deterring other males. This vocalisation behaviour begins at sunset and continues for a few hours into the night over a few weeks during the mating season.
Learn more on our blog: www.aquarium.co.za/blog/entry...

[@hmredacted2123]

It's like they're providing a soundtrack for the sharks

[@simtexa]

Imagine hearing this when having a dive. Very spooky, but also very cool.

[@dylanwise5119]

This is terrifying

[@adrianradu2332]

Mfkers be singing the Jaws theme underwater!

[@watercolourartincapetown2919]

Adorable!!

[@vsauce1066]

Someone is having a bad time in the bathroom