The Red Round (Strawberry) Crab to NOT EAT!

At first glance, the Red Round Crab has the appearance of being cooked to delicious perfection. Furthermore, it also goes by a similarly tasty sounding monikers “Strawberry Crab” and “Red Stone Crab.” The bright rosy red is a telltale sign your crustacean is ready to eat. However, in this instance, such a mistake could be a fatal one! These crabs carry a toxin in their flesh called saxitoxin and tetrodotoxin, if that second one sounds familiar, it's probably because you've heard it mentioned before while learning about pufferfish! Neoliomera insularis is the scientific name of this critter, and while perfectly safe to handle, and even get pinched by it, it is quite toxic to eat. Repeat do not eat this crab, raw or cooked. If you happen to slip and fall, and accidentally consume a Red Round Crab, you're probably dead, there is no antidote for this blend of toxins. Luckily, this isn't a food blog, and most of you are here to learn about cool stuff for your aquarium and the Red Round Crab fits this description perfectly.

Neoliomera insularis comes from all over the tropical Indo-Pacific Ocean, from the south China sea to the warm waters of Northern Australia. They live at a variety of depths, but are usually collected from very shallow water, less than 20 feet deep; most commonly among coral and rock rubble that offers them an abundance of places to hide. They are solitary animals outside of reproduction, in which season they have an elaborate mating display, rarely seen in the home aquarium. They have a brilliant red carapace (shell), and mature individuals can develop bright white, yellow or orange markings on their legs and pincers, and similar colored spots on their shell. They are a very small critter, with adults rarely getting bigger than an inch across the back. They are part of the family Xanthidae, which is one of the largest families of crabs with over 500 species being identified within it!

These crabs are great in captivity. They are peaceful with other crabs and can be kept with others of the same species (even the same sex) if they aren't overcrowded, which is fairly easy with such a small invert. A single specimen could be kept in a tank as small as 10 gallons, and if you wanted to keep more, staying at a 1 per every 10 gallons ratio is a good rule. They don't need much in the way of depth, so focusing on a bigger footprint, (vs more depth) will allow you to keep more of them. We've seen lots of them start to carry eggs, but these usually get eaten by fish before anything else happens to them. If you're interested in captive breeding crabs, there is an opportunity for you here.

They need reef salinity, warm environments; shoot for SG of 1.025 and water temps between 75 and 78. They will grow most quickly and molt most frequently if stable/elevated calcium (350+) and alkalinity (10+) levels are maintained. Like all marine invertebrates, they are extremely intolerant of copper.

When planning your display, include a lot of caves and other places for them to hide. This is a fairly shy crab, and putting some thought into making caves that you can easily see into will allow you to show off their gorgeous colors to more of your friends. Red Round Crabs are surprisingly adept climbers, so be sure to cover your display very carefully, as they can weasel their way through impossibly small holes. There are no real lighting requirements, though as primarily nocturnal critters, they may be more visible, more of the time if lighting is subdued, at least until they become acclimated to daylight feeding. They aren't prodigious diggers, though will do some moderate home expansion in their caves; substrate is not a requirement, but if you choose to include it, make sure the rock work is very stable to avoid crashes.

Neoliomera insularis are grazers and they'll do some detritus clean up but are primarily opportunistic carnivores. We've seen them eat Asterina Stars, and so they could potentially be utilized as control for them. They will also pick at different alga, even some bubble algae, but this is secondary food for them; they will require some meaty sustenance. Here we've been feeding them a meaty mix of food that is appropriately sized for their diminutive size. Things like Gamma Food's Mysis, Loaded Brine, Krill, and Prawn (finely chopped) are great choices, and you'll probably have to target feed these little crabs in order to get enough food to them before it gets stolen by faster fish and other, less shy inverts. While we offer them daily feedings, adults could be fed every other day.

As far as tankmates for these crabs go, they can be kept with most fish, as long as those fish aren't likely to be caught; avoid plodding swimmers like Pipefish and Seahorses. On the other end of the spectrum, these fish are very likely to be eaten by things like Pufferfish, large Wrasses and Triggers, regardless of the crab's toxicity to humans. They are very likely to prey or at least pick on sea stars and pick on other slow or sessile invertebrates like clams and feather dusters. While they are mostly meat eaters, and we consider them reef safe with caution, the fact remains that there just aren't that many of these in the hobby yet. As with any newer crab, there is always some risk in the reef tank. If well fed, this risk can be minimized. If you are determined to go down this pathway, do so with some caution. If you start to see suspicious activity in the display like polyps going missing, increase your feed, or think about re-homing your crabs.

You have a ton of choices for very cool invertebrates to add to your aquarium these days. However, there are VERY few that look this cool; this is easily the most brilliantly colored crab that you're likely to see in your LFS (local fish store). Pretty much nothing in the crab world is going to give you this kind of coloration, and very few other types of inverts can compete either! They get along well with each other and are straightforward to keep. If you're interested in keeping a crab that pretty much no one you know has, ask your LFS to get you some Red Round Crabs from Quality Marine Today!