TankBud

Pom-pom crab

Lybia tessellata

Also known as Boxer Crab, Boxing Crab, Cheerleader Crab

SaltwaterCrab

Pom-pom crab (Lybia tessellata)
Eliot Ferguson · CC BY-SA 3.0

Care at a glance

Temperature
75–81°F
24–27°C
pH
8.1–8.4
Adult size
1 in
2.5 cm
Minimum tank
11 gal
40 L
Temperament
Peaceful
Social behavior
Solitary
Swim level
Bottom
Diet
Carnivore
Difficulty
Easy
Breeding
Hard
Rarity
Rare
Reef safe
Reef safe
Family
Xanthidae
Origin
Indo-Pacific reefs and rubble, including the waters around Indonesia, the Philippines, and the broader tropical Indo-Pacific

Overview

The pom-pom crab is a tiny, secretive crab that suits a calm nano reef. It is easy to keep.

Did you know

The pom-pom crab can clone its anemones. If it loses one, it can split the remaining anemone in two so each claw is armed again.

Caring for the pom-pom crab

Give the pom-pom crab a tank of at least 11 gal (40 L), with plenty of live rock, rubble and hiding spots. It does well in nano to mid-size reefs. Keep the water at 75 to 81°F (24 to 27°C) with a pH of 8.1 to 8.4.

Because it is so small, it is easily outcompeted at feeding time. Target-feed small meaty foods a few times a week.

The pom-pom crab is peaceful and reef safe, and it poses no threat to corals or tank mates. Its anemones make it look armed, but it uses them for defense, not to sting corals. It is more likely to be bothered than to bother anything. Keep it in a calm tank without large aggressive fish or crabs that would eat it.

Good to know

Lybia tessellata is a small crab in the family Xanthidae. It is famous for holding a small stinging sea anemone, typically Triactis or Bunodeopsis, in each claw. It waves them like boxing gloves or pom-poms and uses them both for defense and to sweep up food. It cannot open food with those occupied claws, so it uses its walking legs to pass food to its mouth.

In the wild

The pom-pom crab lives on reefs and rubble across the tropical Indo-Pacific, including the waters around Indonesia and the Philippines. It spends the day tucked into caves and crevices and comes out at night to forage.

Symbiotic relationships

The boxer crab and its anemones

The boxer crab holds a tiny anemone in each claw and waves them at anything that comes close, the way a boxer holds up gloves. The anemones sting for the crab and mop up food particles, and the crab clips food from them to eat. Boxer crabs that lose one anemone have been filmed tearing the other in two, and both halves grow back into a whole anemone, so the crab is farming its weapons. The anemones seem to get nothing but a lifetime of being waved about.

A nano reef animal about an inch (2.5 cm) across that spends much of the day under rock. It is harmless to corals and fish and needs nothing special beyond stable water and no predators. The anemones arrive in its claws and need no care of their own; a crab sold as a pom-pom crab carries Triactis producta or, from the Red Sea, an Alicia. Do not confuse it with the freshwater pom pom crab in this catalog, which has fluffy claws and no anemones at all.

Every symbiotic relationship in the catalog

Common questions

What size tank does a pom-pom crab need?

A pom-pom crab needs at least 11 gal (40 L). It spends most of its time in the bottom.

What temperature and pH does a pom-pom crab need?

A pom-pom crab is comfortable at 75–81°F (24–27°C) with a pH of 8.1–8.4.

What does a pom-pom crab eat?

A pom-pom crab eats small meaty foods. Target-feed it a few times a week, because it is so small that it is easily outcompeted at feeding time.

How big does a pom-pom crab get?

An adult pom-pom crab reaches about 1 in (2.5 cm).

Related species