Sargassum Frogfish: Finding Histrio!

Lying in wait, poised ready for the final attack, its prey has no idea it’s there, only centimetres away, as it uses its final weapon to lure the unsuspecting, soon to be dinner, Sargassum Frogfish? Yes, you read that right, it is also a ferocious cannable!

Sargassum FrogfishFrogfish are one of the most sought after fish by scuba divers, probably due to their strange, ugly, yet beautiful look and it’s interesting, humanlike way in which it catches its prey. The fact that it doesn’t swim off, making it an easy subject for photography, once you find it.
Most of that is still true for the Sargassum Frogfish with a few added oddities thrown in for good luck. First, it doesn’t live down on the reef camouflaged in sponges and corals, it floats up on the surface hanging around in debris most notably sargassum weed, which is where it gets its name and appearance from.

Just like other Frogfish it is a master of disguise blending in with the surrounding environment perfectly, but unlike its close relatives it can change its colour and pattern very quickly, it also has adapted pectoral fins which look more like hands allowing it grab hold of the weed and climb its way through the tangled mess to get to its prey.

Spending most of its time out in the open ocean, floating around on the surface, it doesn’t come across food all that often, so when it does, it eats everything, even other Sargassum Frogfish. Having the ability to open its mouth to consume fish up to twice its own size, and don’t worry about it getting full, its stomach can expand to many times its original size, easily accommodating its prey.

Some of the stories I’ve heard include a Sargassum Frogfish been dissected in the lab, and when they opened its stomach, they found several juvenile Sargassum Frogfish inside, confirming their cannibalistic ways. Another was a lady who was out looking through Sargassum Weed searching for new and interesting critters. This was back in the days when much less was known. She came across a Sargassum Frogfish and decide she would take it home and put it in her saltwater aquarium. The next day there was only one fish left in her aquarium, a big fat floating Sargassum Frogfish!

A little bit of science, of course the Sargassum Frogfish belongs to the Frogfish family (Antennariidae), of the order Lophiiformes. It is the only species within its genus Histrio, its full scientific name been Histrio histrio, in Latin meaning a stage player or actor referring to the way it feeds.

How and where to find them? Well, of course the surface, but that’s a rather big place, so we need to narrow it down. First, look for debris floating around, especially big patches of Sargassum Weed. Once you have found a nice big patch, jump in with a mask and snorkel or on scuba and start the search. If you very gently make your way through the weed, you may disturb a frogfish making it move, this is when you are most likely to spot one. Once you have, watch where it goes and wait for it to settle back down, then sneak up carefully and take your photos, or just enjoy the view.

On the other hand, you can just come visit Magic Island and our amazing staff will show you the way. The best time of year is May to August when the sea is super calm, and the South Westly winds blow surface debris towards the coast of Moalboal. During this time of year you often find lots of Sargassum weed built up against the dive boat at the end of your dives, a great opportunity to look. Or if you’re super lucky you can stand in the dive centre looking down into the ocean as debris passes by and keep a look out, which is exactly what happened to our guest Ladonna Idel. Check out the movie we posted on our YouTube Channel of that amazing occurrence.

It’s an awesome movie showing a few other critters that like to hang out on the surface, also with all the plastic garbage in and amongst the Sargassum Weed it became a bit of a clean-up dive, making it a triple positive reason to jump in!

Written by: Jamie Gladwin
Video credits to: LaDonna Idell
Posted on: July 4, 2022