Red claw mangrove crab

Key Characteristics & Ecology

Physical Appearance: They typically grow to about 4 to 5.5 cm in size. They feature a dark, squarish carapace covered with fine black hairs and distinctive, bright reddish-orange claws (chelae).
Tree-Climbing Behavior: E. mederi is a facultative tree-climbing crab. During high tides, these crabs will climb mangrove trees up to 6 meters high and remain completely still to evade marine predators.
Ecological Role: As burrow-dwelling animals, their digging behaviors cycle nutrients and aerate the intertidal substrate. They are primary consumers of mangrove leaf litter, shredding leaves and speeding up organic carbon turnover within the ecosystem.
Euryhaline Adaptability: They are highly adaptable to changing environments. Laboratory studies show they are strong "hyper-hypo-osmoregulators," meaning they can regulate their internal salt balance in water salinities ranging from 5 to 40 PSU.

Aquarium & Aquaterrarium Care

In the pet trade, they are frequently sold under their historical name Sesarma mederi. If keeping them in captivity, note the following requirements:

Enclosure Setup: They cannot be kept in a standard aquarium. Because they are excellent climbers and need to spend significant time out of the water, they require a secure aquaterrarium (paludarium) with a lid to prevent escape.
Water Parameters: They thrive in temperatures between 21–28 °C and a pH range of 6.0–8.0.
Behavior: They are highly opportunistic omnivores. They will willingly pinch, cut, and eat live aquarium plants to complete their diet and sharpen their claws. They should not be housed with slow-moving or long-finned fish, as they may attack them.