Mudskippers are unique amphibious fish adapted to survive in the challenging intertidal zone of tropical and subtropical regions, such as mangrove forests and estuaries. Their ability to spend significant time out of water, breathing air and moving across exposed mudflats, dictates a highly specialized feeding ecology. This dual existence means their diet is sourced from both the aquatic and terrestrial components of their dynamic habitat.
Primary Food Sources of Mudskippers
Mudskippers exhibit a wide-ranging diet, classifying them as omnivores, although specific food preferences vary by species and location. A major portion of their intake consists of benthic algae and diatoms, which form a nutrient-rich biofilm or mat on the surface of the mudflats. They routinely consume detritus, which is non-living organic matter and fragments of decomposed plant material crucial to the mangrove ecosystem.
Mudskippers rely heavily on small invertebrates found both in and on the mud for protein. This includes small crustaceans, such as copepods, tiny crabs, and crustacean appendages. Polychaete worms and nematodes, which burrow within the sediment, are also regularly consumed.
When the tide is out, mudskippers actively hunt terrestrial prey that lands or crawls on the exposed surface. This terrestrial menu includes various insects, such as mosquito larvae, and other small arthropods. Some species are known to consume small fish or fish scales, demonstrating their capacity for predation on mobile prey.
Specialized Foraging Strategies
Mudskippers primarily forage during low tide when the mudflats are exposed. They use their strong, muscular pectoral fins to “crutch” or skip across the mud, allowing them to pursue prey on land. This movement enables them to locate and consume food outside of the water, a behavior inaccessible to purely aquatic fish.
Carnivorous species, like the Atlantic mudskipper (Periophthalmus barbarus), often employ an ambush strategy, waiting near burrows for small invertebrates to emerge. When a terrestrial prey item is spotted, they execute a rapid lunge, capturing the food with a quick snap of the jaws. Herbivorous species, in contrast, engage in continuous surface skimming, using their mouths to scrape the microscopic layer of algae and detritus directly off the mud surface.
Dietary Variations and Physical Adaptations
The diet of a mudskipper is often linked to its specific genus, reflecting distinct morphological adaptations. Species in the genus Boleophthalmus are predominantly herbivorous, specializing in feeding on diatoms and algae. These species possess flattened or bicuspid teeth that function efficiently like a scraper for harvesting the biofilm from the mud.
Conversely, species in the genus Periophthalmus tend to be more carnivorous, consuming a higher proportion of insects and crustaceans. Their dentition is adapted for this predatory lifestyle, featuring smaller mouths and caninoid, or pointed, teeth used for grasping and puncturing prey. Juveniles of certain species, such as P. koelreuteri, start life as herbivores, relying on diatoms and plant matter, but shift toward a carnivorous diet as they mature.
Physical Adaptations for Terrestrial Feeding
Their success as terrestrial feeders is supported by several unique physical tools. Mudskippers have large, protuberant eyes positioned on top of their head, providing a wide, panoramic view for spotting prey and predators above the substrate. Their highly specialized jaw structure allows the lower jaw to rotate up to 120 degrees, orienting the mouth parallel to the mud surface and enabling them to effectively grab or scoop up small, static prey items on land.