Emerald Crab - Mithraculus sculptus

The Emerald Crab (Mithraculus sculptus) is a popular invertebrate that serves a vital purpose for reef keepers. Its primary job is to control Valonia and Ventricaria bubble algae, also known as Sailor's eyeballs. These algae are a nuisance, spreading quickly and overgrowing corals, often blocking pump inlets.

One of the key benefits of the Emerald Crab is its ability to destroy and consume these algae using its sharp claws. Adding several Emerald Crabs to a mature reef tank can provide natural control, helping to keep the algae growth in check.

While Emerald Crabs are highly useful and popular, it's important to note that they may not be 100% effective at completely eliminating the algae, particularly if more enticing food options are available. However, they are entirely peaceful and can coexist with other inhabitants of a reef tank.

• Key Feature/Benefit 1: Natural control of Valonia and Ventricaria bubble algae
• Key Feature/Benefit 2: Peaceful and compatible with other reef tank inhabitants

One interesting feature of Emerald Crabs is their sexual dimorphism. Males are larger and have bigger claws, while females have an egg flap underneath. In a mature reef tank, female Emerald Crabs may have eggs in their flaps. Unfortunately, raising the young is challenging due to the tiny and pelagic nature of their larvae.

During the daytime, Emerald Crabs often hide out by clinging upside down to the underside of live rocks. To provide them with a suitable habitat, it is recommended to offer plenty of dark and quiet refuges. Avoid combining them with large predators that may pose a threat to the crabs.

Overall, the Emerald Crab serves as a beneficial tool for reef keepers in controlling bubble algae. With their natural predatory abilities, peaceful behavior, and distinctive features, these crabs contribute to maintaining a healthy and visually appealing reef tank.