The biggest challenge in fishing for flatheads here is learning how to do it. There are several reasons why so few anglers try to tackle this fishery. One of the biggest is that they are simply intimidated. The river isn't like a reservoir, where loads of thousands of fish are stocked each week, fish reports are easy to come by and hotspots are well mapped out. Here, you're on your own.

"It's flathead fishing. The locals that do catch them keep it quiet, or they aren't interested in publicizing them," Smothers said. "I met a guy in a trailer park that showed me how to do it. The catfish fishing here is not a moneymaking situation. It's not advertised in the magazines, so no one goes there."

You won't find much about flathead catfish by sifting through local tourism guides, websites and brochures. The marinas sell some fishing bait, but are more concerned with selling beer and ice cream.

"I think there's some big catfish in the river," said a woman at the Blythe Chamber of Commerce, who didn't want to give her name. "But we don't have any fishing information. People come here with their boats. Would you like camping info? I know of a few good places to park your RV."

The California Department of Fish and Game doesn't take an active role in managing the Colorado River. There's simply no need -- the fishery is healthy and maintains itself. No plants are necessary to maintain the catfish population.

"We don't stock it," said Mike Giusti, DFG biologist. "We are well aware of the big flatheads that are there. They are definitely the biggest in Southern California, but we don't do any surveys on them. They get huge, though."

"Huge" may be an understatement. Colorado River flatheads can compete with the gigantic blue catfish found in many SoCal reservoirs. However, flatheads are more available and easier to catch than the elusive and rare blue cats. The river system and its sloughs and canals are loaded with flatheads. Channel cats are well established, but rarely targeted -- most likely because the flatheads are larger.

"I'd say the flatheads here need to be 40 pounds and up to be a big fish," Smothers added. "There might be some 70s or 80s in there. That's what I want to find out.

"I had a huge one on last time. But however big it was, it snapped my 40-pound leader in half. At first, I thought it was something other than a fish. But then I saw the eyes. I was a little scared to try to bring it in the boat. I mean, come on! I can't swim in a river, and I was afraid if I tried to lift it in the boat, it would pull me in.

"But I would have loved to see it. I'd say it was at least 40 pounds. And I know it wasn't a beaver or muskrat. They don't get that heavy or fight that hard."

On the Colorado, knowledge is more than half the battle.

Several factors can play a part in your success. The biggest is casting your live bait into optimal spots.