These tiny Sargassum frog fishes weren’t caught on purpose. They were discovered more than unexpectedly, living in or under a floating fishing net. They only had to be rescued though because we pulled the net out of the water. And a picmybug story was born. Frog fishes are quite rare in the Maldives, and for sure in the South Ari Atoll. Then suddenly so many just float around in the open water?!
Histrio histrio is one of 350 species anglerfish (order Lophiiformes). More precisely, it is a frog fish in the family Antennariidae (50 species). Carl Linnaeus described it in 1758, and the German zoologist Johann Gotthelf Fischer von Waldheim established the genus Histrio in 1813. I thought there must be a name for the circumstance when name and occupation match. And there is. It is an aptronym or euonym when Mr. Fischer studies fishes!
Histrio means harlequin, and it might have been chosen by Linné to describe the pattern and shape of the fish, being spotted and striped lively. The same goes I assume for the harlequin shrimp, dog, duck, rabbit, frog, ladybug, and so on. Harlequins go back to century old tales, and somehow to Erlking, a name that is also used for new car models, whose features are disguised in a pattern-rich camouflage… How modern technology and frog fishes have something in common.
The old fishing net had to be taken out, and for sure it has never been a source of life. But the greenish brown weed growing around it is. And when I find Sargassum frog fishes in it, I will call the algae Sargassum. No guarantee on the ID here, this is new territory for me.
The source of life that is for most species oxygen. Only few larger creatures live an anaerobic live, like a cnidarian parasite (Henneguya zschokkei).
It is said that more or less half of all oxygen in our atmosphere is produced in the oceans. A bacterium, Prochlorococcus marinus, might contribute 20% of all oxygen alone. Read more on www.ocean.si.edu! Though this microalgae is so important, it was only discovered in 1986, and described in 1992. Sallie (Penny) W. Chisholm, the American oceanographer from MIT who was one main actor in this work, gave a fascinating TED talk about it (“The tiny creature that secretly powers the planet“), which can be watched on YouTube.
Guess where they found it. In the Sargasso Sea. That is an ocean gyre east of the Caribbean Sea, named after it’s huge patches of Sargassum. There are some early studies on how much oxygen this gyre produces (Blake and Johnson 1975, Smith Jr. et al. 1973, Hanson 1977), and no surprise, it is a key player in oxygen production, one source of life on our planet. And there’s a whole ecosystem connected to it. Our frogfish is one of them. It can be found in warm waters around the globe, I guess exclusively in floating seaweed. Sargassum is the breeding ground for European eels. Sea turtles, crustaceans, worms and slugs, all can be found and often are specialized on Sargassum.
Since 2011 Sargassum experiences a macrobloom. Climate change, pollution, and probably also natural factors trouble Caribbean states with masses of seaweed. The “Sargassum Abundance Intensity” of the Caribbean Costal Ocean Observing System (CARICOOS) is currently deep red. The Sargassum Watch System monthly publishes the Sargassum Outlook Bulletin (optics.marine.usf.edu). For July 2025, 38 million metric tons of Sargassum were observed, which is more than twice as much as it used to be in the past. They say the growth lost momentum though.
That was a floating frog fish, the tiniest and maybe most important oxygen producer, a macrobloom, an aptronym and harlequins in one picmybug story!
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