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Invasive Species

There are several invasive species that anglers may run across in Delaware waters. We know about northern snakeheads, flathead catfish, and red swamp crayfish but want to get reports to document new sites. There is always the chance you may find something we don’t know about so if you see something you feel is very unusual, please contact us at 302-739-9914. If you do catch any of the invasive species listed, do not return it to the water, but kill it and contact us. Document the catch by freezing it or taking a good photo.

Check out our website ( for more photos and information on invasive species.


Flathead Catfish (INVASIVE)

Introduced flathead catfish have been shown to severely reduce native fish populations and crustaceans. Several individuals have been caught around the first dam in the Brandywine Creek and one from the C&D Canal. They are most easily recognized by their broad, flat head, brown mottled coloration, and lower jaw which sticks out further than the upper.


Blue Catfish (INVASIVE)

These catfish are large, efficient predators that can grow to over 100 lbs. In some Virginia rivers, they now make up 75% of the fish population. They are slate blue with a deeply forked tail and have a straight edge on the anal fin (long fin in front of tail). In comparison, the channel catfish has a rounded (curving out) edge on the anal fin. Also, blue cats never have black spots like those on young channel cats. Blue cats have been found in the Nanticoke River just below the DE / MD line so they are heading to Delaware.


Blue Catfish (INVASIVE) vs. Channel Catfish (NATIVE)

The invasive blue catfish (top) and a native channel catfish (bottom) — note the differences in the anal fins.

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Red Swamp Crayfish (INVASIVE)

A large crayfish with distinctive red bumps on the claws. They often migrate over land during damp weather. They have been found in many locations within Delaware: Brandywine, Dover, Milton, and east of Smyrna. They often are found in stormwater basins within residential developments.


Northern Snakehead (INVASIVE)

This fish has now been reported from: the Nanticoke River, Broad Creek, the Marshyhope, Nonesuch Creek, and Becks Pond. A young snakehead, likely from Becks Pond, was caught below Sunset Lake in fall 2012. It is long and cylindrical, with long dorsal and anal fins and a large mouth with many sharp teeth. Many bowfin (an unusual native species) have been killed and brought in as snakeheads. Be sure to check the photos to confirm the fish’s identification. Bowfin have a short anal fin compared to the long one of the snakehead and adult males have a large “eyespot” at the top of the tail. Bowfin have been found in Dragon Run, C&D Canal, Brandywine Creek, and Nonesuch Creek.


Bowfin (NATIVE)

The native bowfin has a short anal fin as compared to a Northern snakehead and males have an eyespot on upper tail. Please return this native safely to the water.

Regulations in red are new this year.

Purple text indicates an important note.

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