Red Mithrax Crab care guide
Red Mithrax Crab (Mithraculus forceps) — minimum tank 40 L, temperature 24-26 °C, pH 8.1-8.4.
Compiled by Aquairi from published sources · Published · Updated
Overview
Red Mithrax Crab (Mithraculus forceps) is a marine clinging (emerald) crab of the family Mithracidae, listed in the Aquairi knowledge base as a beginner-level species. Reddish-brown Caribbean spider-crab, like a smaller emerald crab. Eats algae and detritus. Well-suited for nano reefs.
Taxonomy
- Family: Mithracidae
- Genus: Mithraculus
- Scientific name: Mithraculus forceps
- Common synonyms: Forceps Crab, Red Emerald Crab
Habitat
Mithraculus clinging crabs (family Mithracidae) are small, flat-bodied majoid crabs of the tropical western Atlantic and Caribbean reefs. They shelter in rockwork by day and graze algae and detritus, and some species associate with anemones. In the Aquairi knowledge base this species is recorded from Caribbean.
Tank requirements
- Minimum tank volume: 40 L (10.6 US gal)
- Adult size: 2-4 cm
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- GH: 8-12 °dGH
- KH: 8-12 °dKH
- Salinity (specific gravity): 1.024-1.026
- Lifespan: 2-4 years
Diet
The species is an omnivore, grazing algae, biofilm and detritus across the rockwork and substrate; in aquaria its diet is supplemented with dried algae and sinking foods when natural growth is scarce.
Compatibility
The Aquairi knowledge base lists this species as peaceful. Suitable tank mates include Reef fish. It should be kept away from Very small fish.
Breeding
Breeding requires an extended planktonic larval stage in open water before the young settle, which makes captive reproduction very difficult and rarely accomplished in home aquaria. Most specimens in the hobby are wild-collected.
Breeding the Red Mithrax Crab (Mithraculus forceps)
Overview
Mithraculus forceps (A. Milne-Edwards, 1875), the red mithrax or red clinging crab, is a small western-Atlantic spider crab resembling a compact emerald crab. It eats algae and detritus and suits nano reefs. It is one of the marine ornamental crabs studied as a candidate for aquaculture because of its short larval cycle.
Sexing
As with other true crabs, sex is read from the abdominal flap: males show a narrow abdomen, females a wide rounded one used to brood eggs. A female carrying a clutch beneath her abdomen is termed ovigerous and signals an imminent larval release.
Spawning & Larvae
The female broods fertilized eggs under her abdomen until hatching. Larval development comprises two zoeal stages and one megalopa. In rearing trials, best survivorship and fastest development came at about 28 °C with larvae fed newly hatched Artemia nauplii, reaching roughly 74% survival to 12 days post-hatch; starved larvae failed to reach zoea 2.
Common Challenges
- Planktonic zoeae are removed by skimmers, filters and pumps in a closed system.
- Larvae require a constant supply of live planktonic food and die quickly if unfed.
- Rearing needs separate larval and megalopa tanks with tight temperature and salinity control.
- Megalopae can show aggressive interactions when crowded, complicating rearing.