Scarlet Cleaner Shrimp

• GeneralIt sets up cleaning stations where it picks parasites out of fishes' mouths.
• comportamientoIt sets up cleaning stations on the reef where larger fish come of their own accord to have parasites and dead skin picked off.
• It advertises its service by waving its white antennae, and the fish — including moray eels and groupers that could eat it — stay still and open their mouths and gills so that it can go in and clean them.
• Every individual first matures as a male and then becomes a hermaphrodite able to act as either male or female, so that any two individuals can breed with each other.
• Fish that visit cleaning stations show lower stress levels, and removing the shrimps experimentally disturbs the whole reef community.
• It sets up cleaning stations: fish stop beside its crevice and wait their turn for it to remove parasites, mucus and dead tissue. It enters the mouths of morays and groupers without fear.
• That service is how it feeds, so the relationship benefits both parties.
• It tells dangerous clients from harmless ones: it cleans predators in a much smaller proportion of encounters, and in front of them it performs a rocking of the legs, almost exclusive to those interactions, that appears to signal its identity or its intention to clean.
• Its reproduction is unique among decapods: it is a protandric simultaneous hermaphrodite. It starts as a male and after a few moults functions as both male and female at once; there is no pure female form.
• A pair staggers its moults in synchrony, because mating happens immediately after one of the two moults.

Habitat and environment

Coral reefs; caves and ledges

Sexual maturity

Matures as a male at around 3.4 cm in total length

Litter / clutch size

Between 200 and 500 eggs per clutch, every two or three weeks

Sources consulted: Dixson et al. (2019), Biology Letters; Fiedler; Wong y Michiels (2011), Frontiers in Zoology