Red mithrax crab
Mithraculus forceps
Also known as Ruby Mithrax Crab, Red Clinging Crab, Ruby Clinging Crab, Red Ridged Clinging Crab
SaltwaterCrab
Care at a glance
- Temperature
- 75–82°F
- 24–28°C
- pH
- 8.0–8.4
- Adult size
- 2 in
- 5 cm
- Minimum tank
- 11 gal
- 40 L
- Temperament
- Mostly peaceful
- Social behavior
- Solitary
- Tankmates
- With caution
- Swim level
- Bottom
- Difficulty
- Easy
- Breeding
- Hard
- Rarity
- Common
- Reef safe
- Reef safe with caution
- Family
- Mithracidae
- Origin
- Western Atlantic and Caribbean, living in coral rubble and reef crevices from Florida to Brazil.
Overview
A single crab suits a tank of 40 litres or more at 24 to 28 C and pH 8.0 to 8.4. It scrapes hair algae, film algae, and some bubble algae off live rock and eats leftover food. A well fed crab is a useful cleaner, but a large or underfed one may start picking at coral polyps or bother small snails, so keep it fed and watch bigger individuals.
In the wild
The red mithrax is a small Caribbean clinging crab with a deep red to reddish brown carapace and blunt spoon-tipped claws. It spends the day wedged in rock crevices and comes out at night to graze. In the wild it lives on offshore reefs rather than the inshore rubble the green emerald crab prefers.
Good to know
Mithraculus forceps is a close relative of the emerald crab, Mithraculus sculptus, and reaches a similar span of about 5 cm across the legs. Its rounded claw tips are built for scraping algae off hard surfaces rather than tearing prey.
Did you know
It is one of the few crabs that will eat bubble algae, the round green Valonia that spreads across neglected rock, which is why reef keepers add it to nuisance algae cleanup crews.
Common questions
What size tank does a Red mithrax crab need?
A Red mithrax crab needs at least 11 gal (40 L). It spends most of its time in the bottom.
What temperature and pH does a Red mithrax crab need?
A Red mithrax crab is comfortable at 75–82°F (24–28°C) with a pH of 8.0–8.4.
How big does a Red mithrax crab get?
An adult Red mithrax crab reaches about 2 in (5 cm).
Related species
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