Channel Catfish vs Flathead Catfish

The check that settles it

Flathead has a squared-off tail, a flattened head and a protruding lower jaw.

Why this matters beyond curiosity

  • Look-alike species often carry different limits. Walleye and sauger, black and white crappie, pike and muskie, blue and channel catfish — each pair can have different sizes, seasons and daily limits in the same water.
  • Check it before the fish goes in the livewell. Most of the tests on this site take seconds and are far easier on a fish you are still holding.
  • If you cannot tell, release it. That is the answer that is never wrong, and it is the one a warden will not argue with.
  • Regulations are set by your state or province and change annually. This site identifies fish; it does not tell you the rules. Check the current regulations for the water you are on.

Ictalurus punctatus

Markings
spots
Body
flat headed, torpedo
Typical size
115 lb
Regulations
Catfish limits vary widely and several states protect trophy-sized fish with maximum size limits. Blue and channel catfish are often managed separately.

Pylodictis olivaris

Markings
mottled
Body
flat headed
Typical size
340 lb
Regulations
Introduced and invasive in several eastern river systems, where states may encourage or require removal. Native-range regulations are quite different.

Confirming a channel catfish

  • Deeply forked tail. Bullheads and flatheads have square or rounded tails.
  • Scattered dark spots, though these fade on large adults.
  • Rounded anal fin with 24 to 29 rays, versus the blue cat's straight-edged fin.
  • Upper jaw clearly projects beyond the lower.

Confirming a flathead catfish

  • Lower jaw projects beyond the upper. Every other North American catfish is the reverse.
  • Tail squared off or only slightly notched, never deeply forked.
  • Broad, flattened head.
  • Mottled yellow-brown colouring.