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his month we stay on the North American continent and go on to a very large catfish from the Ictaluridae family and in a genus all of its own, Pylodictus olivaris. This large cat could be said to be somewhat placed between the genera of Ictalurus and Ameiurus in its appearance and can be found in southern Canada, United States and northern Mexico.

 

Pylodictis olivaris

 

As can been seen in the above picture (and its mouth!) this is not a catfish for the home aquarium and can only be housed when large in a public aquarium facility. They are solitary creatures and inhabit large creeks, rivers and reservoirs, near the cover of rocks, logs or other debris. When young they tend to often live among rocks in a slight current. They are mainly a sport and food fish and specimens of 14-23 kg (30-50 lbs) are not unheard off.

The range of Pylodictus olivaris is SE. Ontario, West Pennslvania, SW. Wisconsin, north Dakota, south to Texas and NE. Mexico; east in Gulf drainages to the Mobile Bay drainage of Alabama, Georgia.

 

 

Pylodictis olivaris - head view

 

In these pictures it certainly looks a fearsome looking beast and when adult it is piscivorous (fish-eating) but when they are young they are predated on by Bullheads and Channel Catfish but soon mature to feed on aquatic insects, crayfish, small fish, worms and then on to the larger fish when adult. The picture below shows a young juvenile of Pylodictus olivaris showing a more mottled and colourful pattern. In common with a lot of large catfish that lose there juvenile markings to become in later life, a more subdued pigmentation. Sexual maturity is not reached until 3-4 years and is said to have a life expectancy of 20 years.

 

 

Pylodictis, anal and caudal fin

 

Bullheads, anal and caudal fin

 

Channel cats, anal and caudal fin

 

 

The shapes of the anal fins are quite distinct with Pylodictis being more rounded than the bullheads and the channel cat has more of a keel shape.

Acknowledgements: Garold W. Sneegas for the use of his photographs. Robin Fischer for providing information on this species.

 

Flathead Catfish

Silurus olivaris, Hopladelus olivaris, Pelodichthys olivaris, Leptops olivaris, Opladelus olivaris

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North America: lower Great Lakes and Mississippi River basins from western Pennsylvania to White-Little Missouri River system in North Dakota, and south to Louisiana in the USA; Gulf Slope from Mobile Bay drainage in Georgia and Alabama, USA to Mexico. Transplanted elsewhere in USA.

155.0cm (5ft-2ins)

08-30°C (45-87°F)

6.0-7.5.

Head large, wide and very flat. Eyes small; mouth wide, lower jaw projecting beyond upper. 4 pairs short barbels. Adipose fin large; dorsal fin spine weak; 14-17 anal fin rays; caudal fin truncate, weakly notched.

Sides olive-yellow to light brown with dark mottling; belly yellowish; caudal fin dark brown to black, with upper lobe unpigmented. Other fins yellowish to light brown.

This is not a catfish for the home aquarium and can only be housed when large in a public aquarium facility.

They first spawn at about 4-5 years old in June and July when water temperatures reach 22-23° C (72-75° F). The flathead, normally a loner fish, pairs up with one of the opposite sex and both the male and female construct the nest. They dig out a large hole under a bank or log or dig down through silt and mud until they reach gravel. They spawn in the nest with the female laying eggs in bunches of 30 to 50. A single female can lay 3,000-30,000 eggs depending on her size. When the female is done, she leaves the nest. The male fans the eggs with his fins. After they hatch, he protects the young until they can feed on their own.

Juveniles feed on aquatic insects, then on to crayfish small fish, worms and larger fish when growing into adulthood.

Pylodictis : Greek, pylos = mud + Greek, ichthys = fish.
olivaris: Means "olive-coloured" in Latin.

Fischer, Robin pers comm.
Knopf; The Audubon Society Field guide to North America Fishes, Whales & Dolphins, 1986.
Smith W.Philip; The Fishes of Illinois, University of Illinois Press. 2002.

Photo Credits

Top two: © Garold W.Sneegas @
Bottom:  © Konrad P. Schmidt