Crabs on the Reef

People often ask “what else” I have in the reef, aside from seahorses:

16D05 Porcelain Crab feeding

Any experienced reefkeeper will tell you that a reef is a little like the original Jurassic Park–we can tell you how many animals we put in the box, but not necessarily how many (or what types) are in there. In my case, it’s less that the animals are breeding unexpectedly, and more that when you work with live rock, hitchhikers happen.

I love crabs, but everything in my tank must “play nicely” with seahorses, which are uniquely susceptible to anything that pinches, bites, or stings. That said, there are a few species of crabs that work well in seahorse tanks–mainly the reef-safe, peaceful species that eat detritus rather than living foods–and I’ve made it my mission to collect as many as my reef will allow.

At present, the crab population consists of:

One Halloween Hermit named “Lazarus.” (He acquired the name because we thought he died the first time he molted, and ended up quite surprised when he emerged from the shell, alive, a few days later.)


Three emerald crabs–who have no names, because it’s difficult to tell them apart, and also because they haven’t been with me long enough to receive or deserve them. If and when they become distinguishable, either in appearance or by behavior, we’ll give them names.

Three porcelain crabs–Ripley, Small, and Alien Queen–who, though not “true crabs,” are easy to spot and smart enough to eat from the feeding tube I use with the seahorses.

16E03 porcelain crabs

Lately, Small and Alien Queen have taken up residence in one of the sea fans, while Ripley pretty much lives wherever she wants.

16E03 Porcelain Crab

I also have about two dozen tiny red-legged hermits, which inhabit shells that range in size from half an inch to an inch and a half in diameter.

16E03 hermit 2

As the hermits grow, I often trade them back to the fish store for smaller ones–a win-win situation because the larger ones are in demand by reef keepers with larger tanks (and more aggressive fish) and by the time mine grow big enough to trade, they figure out how to raid the seahorses’ feeding bowls instead of scavenging leftover food and detritus the way I want them to.

16E03 Crab in bowl

I’m always on the lookout for new or peaceful species that I can introduce to the reef, so stay tuned–there may be more additions as time goes by!

Do you like crabs? Do they freak you out? Would you consider–or have you kept–crabs as pets?

One thought on “Crabs on the Reef

  • May 10, 2016 at 3:32 am

    I did have about a dozen small hermit crabs and about that many anemones when I was a kid. No idea what kind. It was hard to find salt water supplies or help in small town Kansas in the late sixties so eventually the tank kind of ceased by attrition, but we enjoyed them all for about a year or so.

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