Pylodictis olivaris
(Rafinesque, 1818)
|

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.
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.
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.
Spotting the difference between the genus Pylodictus,
Ameiurus and Ictalurus is not too hard. The
caudal and anal fin shapes in the table below show the differences
and also the lower jaw of Pylodictus protrudes while
the jaws of Ameiurus and Ictalurus do not. The
body shape of Pylodictus is also flatter than the other
two genera.
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.
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, crayfish, small fish, worms
and then on to the larger fish when adult.
| Etymology |
Pylodictis :
Greek, pylos = mud + Greek, ichthys = fish
olivaris: Means "olive-coloured"
in Latin |
| Factsheet
Request |
Robin Fischer
|
| Reference |
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 of 
Bottom: Konrad
P. Schmidt |
|
|
| Synonyms:
|
| Silurus olivaris, Hopladelus olivaris, Pelodichthys
olivaris, Leptops olivaris, Opladelus olivaris |
| Common
Name: |
| Flathead Catfish |
| Family: |
| Ictaluridae |
| Subfamily: |
| |
| Distribution: |
| 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 |
| Size: |
| 155cm. (5ft-2ins) |
| Temp: |
| 08-30°C
(45-87°F) |
| pH.: |
| 6.0-7.5. |
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