Booty shakers, starfish torturers, swaying dancers, underwater gunslingers, and candy cane crustaceans. What do all of these have in common? They’re shrimp that you can buy at your local aquarium store! The world of marine invertebrates is infinitely strange, and we aquarists are lucky to have a good chunk of it right at our fingertips.

Harlequin shrimp (Hymenocera picta)

Let’s start things off right with one of the strangest creatures on the list. Somewhere between an orchid flower and a praying mantis in terms of looks, sporting a cream base color dotted with pink to bright blue splotches, the harlequin shrimp is definitely one of the more eye-catching invertebrates you’ll come across in your local aquarium store. It can be hard to figure out which end is the head if you’ve never seen them before!

The harlequin shrimp’s weirdness is not just skin-deep either—it goes way beyond that. First off, they really don’t seem to do as well when kept alone, which is unusual for shrimp. They live in pairs in the wild, defending a joint territory and hunting together. A harlequin can recognize its partner in the dark and will seek them out even when surrounded by other shrimp, which is oddly romantic for a crustacean. When there is no partner present, they move around seemingly restlessly, suggesting stress.

So what do these underwater lovebirds hunt for that requires two shrimp to take it down? The answer is: unsuspecting starfish, sometimes ten times their own size. Harlequin shrimp are obligate echinovores, meaning they feed exclusively on starfish (and sometimes sea urchins, which are also echinoderms). In fact, they really only like the legs, usually leaving the body or “central disk” behind when they’re done snacking.

Because their prey can be very large, harlequins like to pin the starfish on their backs and keep them alive as long as possible so they don’t spoil, slowly eating away at the legs. They use their specialized, extra-sharp front claws to stab their way through the star’s thick skin and reach the soft internal tissue. If you’re not too squeamish, you can observe this in the aquarium—it’s a bit violent, but definitely fascinating to see.

Harlequin Shrimp Hymenocera picta. Photo by Noel Heinsohn

Bongo shrimp (Phyllognathia ceratophthalma )

If you liked the harlequin shrimp, you’ll love this one. Although bongo shrimp (also sometimes referred to as spiny tiger shrimp) have been around in the hobby since around 2008, they’re still rather uncommon—but they have a dedicated niche following among nano reefers in particular.

Although the two species aren’t actually all that closely related, bongo shrimp have a lot in common with harlequins. For example, although with a maximum body length around an inch they’re only half the size, they sport a similarly unusual and somewhat confusing appearance, in this case with orange blotches and blue dots on a white, spiny body.

What really makes the two similar, though, is their diet. Although bongo shrimp aren’t obligate echinovores, starfish are certainly a big favorite of theirs. They don’t tend to catch larger prey, but dine on Asterina and micro brittle stars with particular gusto. Bongos even use a hunting technique similar to that of harlequin shrimp, using their sharp front claws to pin the starfish down, stab it, and rip off pieces of tissue. Ghoulish, but still cool to be able to observe such a specialized creature right in our own homes.

Spiny Tiger Shrimp (Phyllognathia ceratophthalma). Photo by Rickard Zerpe

Pederson’s shrimp (Ancylomenes pedersoni)

Here’s another one for the nano aquarists! Like the bongo shrimp, Pederson’s shrimp only reach about an inch in length. They make up for this in appearance: the species is mostly translucent, but sports a blueish-purple pattern of bands on its four front legs and a dense sprinkling of dots in the same colors on its back. My favorite thing about them, though, is their dance.

As we’ll see below, there are other dancing shrimp, but the Pederson shrimp’s tiny size and long, gangly front claws make its moves all the cuter. These are anemone shrimp, which usually spend most of their lives on or around Bartholomea annulata (the corkscrew anemone), where they blend in quite perfectly thanks to their camouflage-enhancing pattern. However, because pilfering edible bits from their host isn’t enough to keep them alive, they also freelance as cleaners.

Attracting clients isn’t easy when you’re extremely tiny, but Pederson shrimp found the solution. First off, you’ll notice they have the long, white antennae typical of cleaner shrimp; perfect to wave around in order to catch the eye. If the client doesn’t get the memo, they’ll launch into their wavy dance routine. This makes it clear to other reef inhabitants they’re trying to earn a living eating parasites and dead skin bits off much larger—and often predatory—fish.

Pederson’s shrimp (Ancylomenes pedersoni) from Curaçao. Photo: Marijke Puts

Sexy shrimp (Thor amboinensis)

How does a shrimp, off all creatures, end up being nicknamed “sexy”? Well, if the Pederson shrimp’s movements can be described as a sort of interpretative dance involving lots of antenna waving, then the sexy shrimp is their booty-shaking counterpart. This species’ upturned abdomen ensures their butts are constantly in the air, and the fact that they live on anemones means they need to act like anemones do for perfect camouflage—swaying gently in the flow just like their host’s tentacles.

Aside from its sexy dance, Thor amboinensis has also made it onto the list thanks to its appearance. The strange stance is one thing, but what about those bright white eyes, the amber body, and those white blotches perfectly outlined in neon blue? Though tiny (less than an inch in length), sexy shrimp are sure to catch the eye.

Interestingly, Pederson’s and sexy shrimp sometimes occur alongside each other in the wild. Where the former earns the majority of its keep by cleaning groupers and other big-toothed fish, the latter is a bit more of a freeloader. Sexy shrimp rarely venture out to forage, preferring to pick edible bits off their host. If those are scarce, they may also begin to munch on the anemone’s own tentacles or mucus.

Sexy Shrimp (Thor amboinensis) from Cebu, Philippines. Credit: Klaus Stiefel

Randall’s pistol shrimp (Alpheus randalli)

If you’ve ever met a pistol shrimp, then you know that the genus Alpheus is a delightfully wacky one. The concept of a pistol-owning crustacean is a pretty unusual one to say the least, and yet almost all members of this genus carry an oversized claw that doubles as a deadly underwater firearm.

Pistol shrimp are also known as snapping shrimp, which is actually a more accurate denomination (although tiny underwater pistols do speak to the imagination). That big claw can be snapped closed with incredible power for a little crustacean; depending on the species of pistol shrimp, the pressurized bubbles released when they ‘snap’ can be powerful enough to prove fatal to smaller fish.

Now, Randall’s pistol shrimp is not the biggest, baddest gunslinger in the West—that title goes to the bigclaw snapping shrimp (Alpheus heterochaelis), in my opinion. But bigclaws aren’t much to look at, while a Randall’s red and white banded pattern makes it a wonderfully colorful addition to the aquarium.

Although their powerful, asymmetric claws are more than enough to land pistol shrimp on this list, that’s actually not their weirdest characteristic. What’s stranger is that many species have fish best friends. Their finned besties are gobies, a logical choice for a bottom-dweller. The two species live together in perfect symbiosis, with the shrimp using its large claw to maintain a cozy burrow for the two pals, while the goby keeps an eye out for danger.

Check out the fascinating dynamics of pistol shrimp and gobies in “The Life of Gobies & Pistol Shrimps” by Francesco Ricciardi!

A Flag-Tail Shrimp-Goby Amblyeleotris yanoi sharing his burrow with the colorful shrimp Alpheus randalli. Photo: Francesco Ricciardi

Zebra mantis shrimp (Lysiosquillina maculata)

So far, the shrimp we’ve discussed have been pretty tiny, with the harlequin shrimp topping the length chart at a measly 2”. Don’t worry: if you’re looking for something bigger and significantly badder, I’ve got just the thing for you. The zebra mantis shrimp—technically not a true shrimp, but close enough in my opinion—reaches more than a foot in length and can weigh over 2lbs.

This freakishly large, stripey crustacean is truly the thing of nightmares (unless, like me, you think even the freakiest inverts are cute). Unlike the more well-known peacock mantis shrimp, which clubs its prey to death, the zebra mantis is of the “spearer” variety. Its technique is indeed very reminiscent of a praying mantis, with spike-lined grabby arms impaling prey instantly, keeping it firmly in place as the shrimp moves itself and its catch back into its lair.

A monster invert like this one may look like it needs a massive tank, but mantis shrimp are not the most active creatures. Zebra mantises will spend much of their day (half) hidden in their lairs, waiting for unsuspecting prey to swim or crawl by. A relatively tall set-up of around 50 gallons should work well; use a very deep sand bed so your shrimp can burrow comfortably.

Aquarists generally find zebra mantis shrimp to be hardy and forgiving, though keep your hands away from those imposing spears! As you can probably imagine, to prevent carnage, you should skip the tankmates and go for a single-species set-up if you want to keep this huge invertebrate.

Bumblebee shrimp (Gnathophyllum americanum )

Right, back to something of more normal proportions, shall we? Although the bumblebee shrimp features a banded pattern similar to that of the aforementioned zebra mantis shrimp, it only grows to around an inch in length. Consequently, it’s a lot less creepy and violent. Just don’t confuse it with the freshwater bumblebee shrimp, which belongs to a completely different species scientifically known as Caridina breviata.

Marine bumblebee shrimp sport a squat body with a white to yellow base and black stripes running across the body. The claws, legs, and tail feature pops of orange to yellow, making this shrimp a rather pretty eye-catching addition to the aquarium (especially nano tanks) despite its small size.

Like bongo shrimp, but unlike harlequins, bumblebee shrimp are non-obligate echinovores. Their favorite foods are starfish, sea urchins, and sand dollars, although they won’t starve if these are unavailable. You can offer yours normal frozen reef foods, although it’s pretty fun to toss in a starfish now and then to see this tiny shrimp display its hunting skills!

Did you know? G. americanum isn’t the only member of its genus kept in the aquarium. If you like polka dots more than bumblebee bands, you can also opt for the spotted bumblebee shrimp (G. elegans). It can be a little more difficult to find, though.

Bumblebee shrimp (Gnathophyllum americanum ). Photo by Nathalie Rodrigues

Coral banded shrimp (Stenopus hispidus)

The coral banded shrimp isn’t technically a true shrimp, although what constitutes a “true shrimp” is a commonly debated subject anyway. The species looks similar enough to me, anyway—except for those freakishly big front claws! Who wants to give the CBS a nice, big hug?

Stenopus hispidus is only one member of a genus containing several strange shrimp, including the blue-bodied S. tenuirostris. It’s by far the most commonly available of the Stenopus in the aquarium hobby, though, and has become quite a popular choice for tanks of 30 gallons and up despite its somewhat spicy, territorial disposition.

Coral banded shrimp aren’t your average, inch-long, pacifist sexy shrimp; they didn’t actually evolve those big claws for hugging purposes, after all. These 2.5”, spiky crustaceans mostly perform cleaning activities in the wild, but in lieu of suitable clients, they will consume anything from annoying pest worms to smaller shrimp, snails, and other inverts. They’ll also ruthlessly attack each other unless you get a bonded pair, so be very careful if you’re planning on combining multiple.

Coral banded shrimp (Stenopus hispidus) from the Thai Andaman Sea. Photo: Marijke Puts

Marijke set up her first aquarium when she was just 13 years old—and hasn’t looked back since.

Today, she’s a pop science writer specialized in marine biology and fishkeeping (fresh + saltwater), avid scuba diver and underwater photographer, and proud owner of a 30-liter reef cube.

Sources & further reading

Bos, A. R., & Hoeksema, B. W. (2015). Cryptobenthic fishes and co-inhabiting shrimps associated with the mushroom coral Heliofungia actiniformis (Fungiidae) in the Davao Gulf, Philippines. Environmental Biology of Fishes, 98, 1479-1489.

Prakash, S., & Kumar, T. A. (2013). Feeding behavior of Harlequin shrimp Hymenocera picta Dana, 1852 (Hymenoceridae) on sea star Linckia laevigata (Ophidiasteridae). Journal of Threatened Taxa, 5(13), 4819-4821.

Seibt, U. (1973). Sense of smell and pair-bond in Hymenocery picta. Micronesia, 9, 231-236.

Vadher, P., Kardani, H., Dabhi, R., & Beleem, I. (2024). New distribution record of the rare spiny tiger Shrimp, Phyllognathia Ceratophthalma (Balss, 1913), along the Indian Coast. National Academy Science Letters, 1-5.