Meet the Idiomysis Shrimp, the Social Butterfly of the Ocean

Basically, Idiomysis shrimp are cute, social and love to dance

Recently, while looking at underwater macro photography, I stumbled across an adorable type of shrimp that I had never seen before. Their bulging eyes and tiny, colorful bodies were simply too cute to handle. I wanted to learn more. Surprisingly, a Google (and even Bing!) search showed me that there is very little written about these interesting critters. My curiosity aroused, I took it upon myself to highlight this underappreciated—yet charming—type of shrimp. As I researched, I began to feel a connection to and kinship with these little crustaceans. Here are a few reasons why the Idiomysis is my new favorite genus of mysid shrimp.

Idiomysis shrimp are small in statureand elusive

Idiomysis shrimp are minuscule crustaceans that reach a size of about 3-5 millimeters. That means they are less than one centimeter in length! These delightful beings can be found from the warm, shallow waters of the Indian Ocean (including the Red Sea) to the Pacific Ocean. This area includes Australia, Japan, East Africa, Egypt and Indonesia. Besides being diminutive and international, these shrimp are also notoriously difficult to find! If you’d like to view them in person, divers have seen them in the Lembeh Strait near Manado, Indonesia—a macro photography haven.

They are unique and can’t be “tamed”

There are only seven known species of these elusive socialites, one of which was discovered only last year: Idiomysis bumbumiensis (2021), I. diadema (2016), I. robusta (aptly named as they are the largest at a whopping 6 mm; 2008), I. mozambica (2001), I. japonica (1978), I. tsurnamali (1973) and I. inermis (1922). In fact, there really isn’t much information or research available about them. They are extremely difficult to keep alive in captivity, so marine scientists haven’t had much opportunity to observe them outside of the wild. While I’d love to learn more, I like that they maintain a little bit of mystery.

Macro shot of idiomysis shrimp, tiny crustaceans with big eyes.

They love to socialize

Like me, the Idiomysis loves to party! Many of the photos show these chummy crustaceans congregating in large groups, as confirmed by the marine scientists who have studied them. In all seriousness, their small stature and vibrant colors of red, purple and yellow make them a conspicuous snack for larger predators, and, consequently, they find safety in numbers. They are highly social and prefer to hang out in large groups of five to forty, though a few lucky photographers have captured hundreds together.

 They love to dance

Also like me, these shrimp are rarely spotted resting. If you are lucky enough to come across one in the wild, you’ll find these extroverts appear to resemble a swarm of bees hovering over a blooming garden or a group of friends enjoying a night on the town. They gracefully sway around the water in place, and you won’t be able to resist smiling at the sight of twenty or thirty synchronized Idiomysis bobbing and bopping around a coral reef “dance floor” or seaweed “night club.”

There you have it! Everyone has a land or marine animal that they identify with or see a bit of themselves in, and for me, it’s a carefree, nearly microscopic shrimp! Regardless of their size, they add immeasurable value, diversity and cuteness to coral reef ecosystems, and they’ve made quite a big impact on me.

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