Fiddler crabs are characterized by a compact, robust carapace that ranges in color from earthy browns to vibrant reds and oranges, often adorned with patterns that help them camouflage in their muddy or sandy environments. They typically measure between 2 to 5 cm in body width, although some species can be slightly larger. The large claw serves as a display weapon, used not only for defense but also for attracting mates during courtship rituals. The smaller claw, on the other hand, is used for feeding, sifting through the substrate to find organic matter, algae, and detritus.

In terms of their behavior, fiddler crabs exhibit complex social structures with males actively defending territories around their burrows, often engaging in claw-waving displays to intimidate rivals or attract females. The burrows they construct are vital to their survival, offering protection from predators, a stable microclimate, and a refuge for molting and breeding.
Fiddler crabs exhibit significant adaptability to their environment, thriving in areas that experience fluctuating tides. Their unique physiological and behavioral traits allow them to live both in aquatic and terrestrial conditions, emerging from their burrows during low tide to forage and socialize, and retreating to the safety of their burrows as the tide rises.