Hawaiian Pom Pom Crab
From Microcosm Aquarium Explorer
Note pair of small anemones, Triactis producta. David Burdick/NOAA
Overview
Known as kūmimi pua (inedible blossom) to native peoples, this is a tiny Hawaiian endemic species that sometimes enters the aquarium trade.
In a fascinating case of symbiosis, this crab holds small Crab Claw Anemones (Triactis producta) in its claws and waves them at a potential threat as if it is boxing. These tiny anemones reportedly have potent stinging ability.
It may also use its “pom poms” to "mop" detritus, which it then feeds on. (The anemones benefit from being waved in the water column when food is passing by.)
Curiously, lab studies have shown that a crab that loses one anemone will attempt to split the one it has left into two regenerated clones, a method used by humans to propagate larger anemones.
This crab is attractively marked, with striped legs and bold markings on its carapace. Its markings appear to exaggerate the size of its eyes, likely to confuse predators. (A very similar species is more commonly imported. See: Pom Pom Crab.)
They may be kept in groups and females will produce reddish colored egg masses that they carry on their abdomens. The pelagic larvae are called zoea.
According to The Hawaiian Dictionary, this and other xanthid crabs were used in folk sorcery and medicine.
Family: Xanthidae
Other common name(s):
- Boxer Crab
- Pom Pom Crab
Native range:
Habitat: Inshore areas, coral reefs.
Maximum length: 1.6 cm (1 in)
Minimum aquarium size: 8 L (2 gal)
Water: Marine 24 °C (75 °F) - 28 °C (82 °F)
General swimming level: Bottom.
Feeding
Omnivore. Will feed on detritus and small food particles that it picks off the substrate or that adhere to its anemone partner. Should attempt to target feed with finely chopped, meaty foods. Without sufficient food, the anemones may not survive.
Aquarium Compatibility
An ideal invertebrate for a nano tank. It is reef safe, but in a larger aquarium it is likely to disappear. Prone to being eaten by a number of carnivorous fish species, but some may be deterred by its stinging anemones. Large dottybacks, hawkfishes, wrasses, sand perches, and puffers may attack them. Hermit crabs may harass Pom Pom Crabs. It will not harm any of its tankmates.
Special Care
A cryptic species that must be provided with rubble, rocks, and crevices to hide under or in. If well cared for, it will live for several years in captivity.
Breeding/Propagation
May produce eggs in captivity.
Notes
There are at least two species sold as Pom Pom Crabs that enter the trade: Lybia tesselata (Indo-Pacific) and this species L. edmondsoni (Hawaiian Islands). See: Pom Pom Crab.