Atlantic mudskipper

Geographical Origin and Habitat: Periophthalmus barbarus, commonly known as the Atlantic mudskipper, is native to the coastal regions of West Africa. Its natural distribution ranges along the Atlantic coasts from Senegal to Angola, including countries like Nigeria, Cameroon, and Gabon. Its habitat consists of estuarine mangrove forests, muddy tidal flats, brackish swamps, and coastal lagoons. It lives in environments subject to strong tidal variations, spending most of its time on dry, muddy banks.

Taxonomy and Morphology: It belongs to the class Actinopterygii, order Perciformes, family Gobiidae, subfamily Oxudercinae, and genus Periophthalmus. It exhibits extraordinary morphological adaptations to terrestrial life: the pectoral fins are muscular and jointed, functioning like actual legs to walk and jump on the mud. The eyes are large, protruding, positioned on top of the head, and independently mobile. Adults reach a length between 15 and 20 centimeters (6 to 8 inches).

Social Behavior: It is an extremely territorial, active, and aggressive fish toward conspecifics. Males establish individual territories on muddy flats and defend them vigorously by raising their colored dorsal fins, performing intimidating jumps, and chasing away intruders. It has predominantly diurnal habits and is an amphibious animal: it breathes atmospheric air by storing water in its large gill chambers and breathing through its wet skin.

Coloration and Sexual Dimorphism: The body presents a cryptic grey-brown or greenish coloration with dark mottling and small iridescent blue spots on the sides. It has two dorsal fins; the first is dark with a bluish or white band on the margin. Sexual dimorphism is minimal: mature males are slightly larger than females and show much more intense and contrasted colors during the courtship and territorial combat periods.

Aquarium Setup: Requires a specific paludarium setup (minimum capacity of 150 liters, at least 100-120 cm long). The setup must provide about 70% land area (fine sand, aquarium mud, flat rocks, and mangrove roots or driftwood) and 30% shallow water area (maximum 10-15 cm deep). It is essential to install a tight-fitting lid, as these fish are exceptional climbers and can escape through very small gaps.

Diet and Feeding: It is an insectivorous and carnivorous predator that prefers to feed on land. In the aquarium, it must be fed live food placed on dry areas: small crickets, fruit flies (drosophila), mealworms, and small earthworms. It also accepts frozen foods like bloodworms, krill, and brine shrimp placed on wet rocks. Avoid throwing food into deep water where the mudskipper struggles to catch it.

Water Quality: Requires brackish water with specific gravity maintained constantly between 1.005 and 1.012, achieved by dissolving specific marine aquarium salts. The water temperature must be between 25°C and 28°C (77°F - 82°F), while the air temperature above the land zone must be heated to 26-30°C (79°F - 86°F) using spot lamps. Air humidity must be very high (80-90%) to prevent the skin from drying.

Compatibility and Cohabitation: It is highly recommended to house it in a single-species tank. Due to strong intraspecific territorial aggression, keeping multiple specimens requires huge paludariums (over 150 cm long) equipped with numerous visual barriers (rocks and wood) to define territories. Fast brackish surface fish can be kept in the water area, but small tankmates will be preyed upon.

Aquarium Breeding: Breeding in the aquarium is extremely difficult and rarely documented in captivity. In the wild, males dig deep Y-shaped burrows in compact mud, where they carry air bubbles to oxygenate the internal spawning chamber where the female will lay eggs. Larvae develop in water during high tide. Recreating this microhabitat at home requires complex setups.

Risks and Diseases: The primary biological risk is skin dehydration: if the fish escapes the paludarium or if air humidity drops below critical levels, it dies in a short time. It is prone to bacterial skin infections (fin rot) and fungal diseases if land hygiene is poor or mud decomposes. Wounds from frequent territorial fights between males can become infected if the water is not clean.