Common name: Convex Reef Crab

General Information

The Convex Reef Crab, scientifically known as Carpilius convexus, is a strikingly beautiful crab species found in tropical and subtropical reef environments. Its carapace is adorned with a unique pattern of red and white blotches, making it a visually appealing addition to any marine aquarium. This species is also commonly referred to as the Humpback Crab due to the distinctive convex shape of its carapace.

While not as commonly kept as other marine invertebrates, the Convex Reef Crab has gained attention among hobbyists for its fascinating behavior and striking appearance. However, its suitability for reef aquariums is a topic of debate due to its opportunistic feeding habits.

Care

The Convex Reef Crab is relatively hardy and can adapt to a variety of tank conditions, making it a good choice for experienced aquarists. They require a well-established tank with plenty of live rock to provide hiding spots and mimic their natural reef habitat. These crabs are nocturnal and will often hide during the day, becoming more active at night.

Due to their opportunistic nature, they may pose a risk to smaller tank inhabitants, including fish, invertebrates, and corals. Careful consideration should be given before introducing them to a reef tank.

Diet and Feeding

In the wild, Carpilius convexus is an omnivore, feeding on a variety of foods, including algae, detritus, and small invertebrates. In captivity, they should be offered a varied diet that includes meaty foods such as shrimp, squid, and crab pellets, as well as algae-based foods to mimic their natural diet.

Feeding should be done sparingly, as overfeeding can lead to water quality issues. Observing their feeding behavior can also help gauge their dietary preferences and ensure they are receiving adequate nutrition.

Behavior and Compatibility

The Convex Reef Crab is semi-aggressive and should be housed with caution. While they can coexist with larger, more robust tank mates, they may prey on smaller or more delicate species. Their territorial nature means they may claim a specific area of the tank as their own, defending it from intruders.

They are not considered reef-safe due to their tendency to nip at corals and other invertebrates. Hobbyists should carefully monitor their behavior and be prepared to relocate them if they pose a threat to other tank inhabitants.

Habitat

Naturally found in coral reefs and rocky substrates across the Indo-Pacific region, including the Red Sea, the Convex Reef Crab thrives in warm, shallow waters with plenty of hiding spots. Replicating these conditions in captivity is essential for their well-being.