Channel, Blue or Flathead? Three Catfish, Three Checks

Two of these three are genuinely easy to confuse, and one is not the same kind of animal at all.

Start by asking whether the lower jaw sticks out.

Flathead, straight away

• Lower jaw projects beyond the upper. Nothing else here does.
• Head broad and flattened from above.
• Mottled yellow-brown and olive, often called a yellow cat or shovelhead.
• Tail squared off, barely notched.
• Eyes small and set high, angled upward.

Flatheads are also solitary ambush predators that eat live fish almost exclusively, so a flathead in a bucket of channel cats caught on cut bait is unusual on behaviour alone.

If the jaws are even, or the upper overhangs, you have a channel or a blue, and now the anal fin does the work.

Channel against blue: the anal fin

Spread the anal fin — the long fin on the underside, ahead of the tail — and look at its outline and count its rays.

The shape is the field version: a blue's anal fin has an outer margin you could put a ruler against; a channel's curves. The count is the version that settles an argument, and it does not overlap.

Colour and spots are what everyone reaches for and neither survives contact with a real fish. Young channel cats are spotted; large ones often are not. Both species darken and pale with turbidity and with the substrate they have been sitting on.

Bullheads

Smaller, and separated from the three above by the tail.

• Tail squared or only slightly notched — bullhead. Channel and blue both have a deeply forked tail.
• Black bullhead: black chin barbels, a pale bar at the tail base.
• Yellow bullhead: white or yellow chin barbels, which is the fastest bullhead character there is.
• Brown bullhead: mottled, with dark barbels and strong serrations on the pectoral spine.

A squared tail plus a projecting lower jaw is a flathead; a squared tail with even jaws and a small body is a bullhead.

Why it matters

Regulations increasingly separate blues from channels, particularly where blue catfish have been introduced outside their native range and are now managed as an invasive — the Chesapeake tributaries are the well-known case, where blues are under removal pressure and channel cats are not.

Trophy-size limits also frequently apply to blues and flatheads and not to channels. Getting the anal fin count right is worth the thirty seconds.

Handling

All three have serrated spines in the dorsal and pectoral fins, and all three can drive one through a hand. The venom in the associated glands is mild but the puncture is what causes the trouble.

Grip a small catfish from above with the palm behind the dorsal spine and thumb and fingers behind the pectoral spines. For anything large, use a lip grip or support the body — do not try the hand grip on a fish you cannot span.

The barbels are entirely harmless. The persistent belief that catfish sting with their whiskers has caused a lot of unnecessary care with the wrong end of the fish.

The general point

As with pike and muskie and the crappies, the character everyone uses — colour — is the one that varies most, and the reliable one is countable. That skill is worth having in general: counting fin rays and spines.