Eels are aquatic creatures found globally. Primarily predatory, their carnivorous diet and prey selection are influenced by species, habitat, and developmental stage.
What Eels Generally Eat
Eels are carnivores, eating varied smaller aquatic organisms. Their common prey includes small fish, crustaceans (crabs, shrimp), mollusks (snails, clams), and worms. Freshwater eels also eat insect larvae. Eels are opportunistic feeders, taking advantage of available food, including carrion.
Dietary Variations Among Eel Species
Eel diets vary significantly by species and habitat. Freshwater eels, like American and European eels, feed on aquatic insects, larvae, small fish, frogs, and crayfish in rivers and lakes. They also consume worms, clams, and other mollusks.
Moray eels, found in coral reefs and rocky crevices, are opportunistic. They consume fish, octopuses, and crustaceans. Some moray species, like the snowflake or zebra, have blunt, molar-like teeth to crush hard-shelled prey. They often hide in crevices during the day, emerging at night to feed.
Conger eels, inhabiting deeper waters, primarily feed on crustaceans, shrimp, and small fish. They also consume cephalopods like squid and cuttlefish, and occasionally other eels. Congers are bottom feeders and can be opportunistic, scavenging for dead fish.
Garden eels, with their burrowing lifestyle, primarily eat plankton and small invertebrates. They remain within burrows, swaying to catch microscopic organisms. Their small mouths reflect their tiny prey diet.
How Eels Hunt and Feed
Eels use various strategies to acquire food, relying on physical adaptations and senses. Many are ambush predators, hiding in crevices, burrows, or rocks, striking quickly when prey approaches. Their flexible bodies allow them to maneuver into tight spaces for hidden prey.
Many eel species are nocturnal, hunting at night. Despite poor eyesight, eels compensate with a highly developed sense of smell. This strong olfactory sense helps locate prey in dark or murky waters.
Eels have specialized mouths and teeth to capture slippery prey. Their sharp, backward-pointing teeth grip fish and other organisms, preventing escape. Some moray eels can dislocate their pharyngeal jaws to pull prey deeper into their throats. Eels have strong jaws and can swallow prey whole or tear larger items.
Dietary Changes Through Eel Life Stages
An eel’s diet transforms through its life stages, adapting to changing morphology and habitat. The initial larval stage, leptocephali, are transparent, leaf-like creatures drifting in ocean currents. Their primary diet is marine snow, composed of detritus, plankton, and other organic matter.
As leptocephali develop into glass eels, they migrate towards coastal and freshwater environments. Their diet shifts to include smaller invertebrates, such as tiny crustaceans and insect larvae. Elvers continue this diet, feeding on insect larvae and small fish as they move into freshwater systems.
Adult eels consume varied and larger prey. As they grow, their diet expands to include larger fish and crustaceans. This shift from microscopic marine snow to substantial prey highlights the adaptability of eels throughout their life cycle.