Candy Striped Hermit Crab: The Caribbean Jewel

If you are passionate about rare and interesting crabs, then you need to know about the candy striped hermit crab. The small, vibrantly colored hermit crab scientifically known as Pylopaguropsis mollymullerae can’t be caught due to its protected status and elusive nature through the aquarium trade. Still, it’s a sight to see for divers into the colorful reefs of Bonaire. We are taking a dive and finding out what there is in store to amaze you about this little crustacean.

The Candy Striped Hermit Crab is a bright ocean jewel instantly identifiable by the red-and-white candy cane-like stripes of coloration across its body. It is a very small species, attaining lengths of only 0.9 to 2.4 mm. What makes this hermit crab so distinctive, however, is its greatly oversized scoop-like right pincer. Specially adapted in shape for pushing the crab forward along the bottom, this claw is quite unlike any other in the hermit crab world. It has very long, hair-like antennae, adding to its peculiar appearance, making the animal closely resemble shrimp that are associated with fish-cleaning behaviour.

This colourful hermit crab inhabits the beautiful coral reefs of Bonaire’s National Marine Park. It is usually found hiding in crevices under rock overhangs at 13.7 meters depth, sometimes sharing dens with the flaming reef lobsters, Enoplometopus antillensis, or broad-banded moray eels, Channomuraena vittata. They are very shy kinds of crabs and like to remain in small enclosures, thus making them hardly available to even skilled divers. In case one gets the opportunity to see them, their bright colors are indeed a treat to watch.

Probably the most interesting aspect of this hermit crab is the fact that it might act as a “cleaner” or “den commensal.” This crab has been observed to crawl on moray eels by divers, apparently feeding on mucus or other particles on the fish’s skin. This would almost certainly point to a symbiotic relationship, much like some shrimp that clean fish by removing parasites or debris. While further research is required to confirm this behaviour, it certainly paints an interesting picture of the potential bond that may form between this tiny hermit crab and much larger marine animals, such as moray eels.

While this tiny hermit crab isn’t common in the aquarium trade, let’s look at what would be needed if you could keep it in a saltwater tank setup.

For for candy striped hermit crabs, a well-established saltwater aquarium of at least 5 to 10 gallons is ideal, depending on the number of crabs. Since these crabs are tiny (only about 2-3 mm long), you won’t need a large tank, but it’s crucial to have a stable, healthy marine environment.

Use a mix of fine sand and crushed coral as the substrate. This mimics their natural reef environment and allows them to scavenge and burrow comfortably. A substrate depth of about 1-2 inches is sufficient since these crabs are small and prefer hiding in crevices or under rocks.

Maintaining stable saltwater conditions is key for candy striped hermit crabs’ health. Here are the ideal water parameters:

• Temperature: 25-27 °C (77-80 °F)
• Salinity: 1.023 to 1.025 specific gravity (standard reef salt levels)
• pH: 8.1-8.4
• Ammonia/Nitrite: 0 ppm
• Nitrate: