Common name: Nodose Clinging Crab

General Information

The Nodose Clinging Crab, scientifically known as Mithraculus coryphe, is a fascinating addition to marine aquariums, particularly for hobbyists looking for natural algae control. This small, hardy crab is often referred to as the "Emerald Crab" due to its greenish coloration, though it can also display brownish tones depending on its diet and environment. Its compact size and peaceful nature make it a popular choice for reef tanks.

Native to the tropical waters of the Western Atlantic, including the Caribbean, Mithraculus coryphe is a nocturnal scavenger that spends its time clinging to rocks and corals, foraging for algae and detritus. Its unique appearance, with a carapace covered in small nodules, adds an interesting aesthetic to any aquarium.

Care

The Nodose Clinging Crab is relatively easy to care for, making it suitable for aquarists of all experience levels. It thrives in well-established reef tanks with plenty of live rock, which provides both food and shelter. While it primarily feeds on algae, it will also consume detritus and leftover food, contributing to the overall cleanliness of the tank.

This species is reef-safe with caution, as it may occasionally nip at soft corals or small invertebrates if food is scarce. Providing a consistent food source, such as algae wafers or blanched vegetables, can help mitigate this behavior.

Diet and Feeding

In the wild, Mithraculus coryphe primarily feeds on algae, including nuisance varieties like hair algae. In captivity, it should be offered a diet that mimics its natural feeding habits. Supplement its diet with algae-based foods, such as spirulina pellets or nori, as well as occasional meaty treats like mysis shrimp or finely chopped seafood.

Feed the crab every other day, ensuring that it has access to food without overloading the tank with nutrients. Observing its foraging behavior can help determine if additional feeding is necessary.

Behavior and Compatibility

The Nodose Clinging Crab is generally peaceful and spends most of its time hiding among rocks or foraging for food. It is compatible with a wide range of reef-safe fish and invertebrates, though caution should be exercised when housing it with very small or delicate species.

This crab is not aggressive but may defend its territory if provoked. It is best kept singly or in small groups in larger tanks to avoid territorial disputes. Providing ample hiding spots can help reduce stress and aggression.

Health and Common Issues

With proper care, the Nodose Clinging Crab can live for several years in captivity. It is a hardy species but can be sensitive to sudden changes in water parameters. Maintaining stable conditions and providing a balanced diet are key to its health.

When selecting a specimen, look for a crab with intact legs and claws, as well as a healthy, active demeanor. Avoid individuals with damaged appendages or signs of lethargy.

Habitat

In the wild, Mithraculus coryphe is found in shallow reef environments, often clinging to rocks and coral heads. It prefers areas with abundant algae growth, which serves as both food and camouflage. Replicating this environment in captivity with live rock and moderate water flow will help the crab feel at home.