Coon Rapids, Minn. ? Carp fisherman Bob Siegel dug into a bag containing tiny bottles to search for his secret weapon.

He reached past a bottle containing a mysterious concoction from South Africa. He dug past bottles of anise and banana flavors and past a brown vial labeled “strawberry.” His hand settled on a perfume-sized bottle recently shipped from Chicago, the one with an eyedropper and a tiny label with cryptic lettering.

In a low voice, the 3M engineer revealed its name.

“It’s called ‘Obsession for Carp,'” Siegel said. “It looks like soy sauce, it smells like soy sauce, but I’m sure there’s some secret ingredient.”

Siegel drizzled some of the liquid on a ball of white bread and sent the bait whizzing into the Mississippi River above the Coon Rapids dam. Before long, he was fighting a carp, a species he calls the “biggest and hardest-fighting fish around.”

Carp might be the Rodney Dangerfields of the fish world, but Siegel is obsessed with the fish, and so are a few of his friends.

On a Friday morning, Siegel lined up along the Mississippi with fellow carp addicts Jim Collins and Dave Moran to scope out conditions for the annual Coon Rapids Carp Festival. Collins had driven from Princeton, Minn., but Moran had driven all night from Decatur, Ill., to meet his carp buddies, whom he only knew from Internet contact.

“We met in the Carp Anglers Group chat room,” Moran said.

“Just what parents warn their kids about,” Siegel joked.

They showed up with enough sophisticated fishing gear to make Roland Martin look like a cane-pole amateur.

Developed mostly in the United Kingdom, carp fishing gear bears little resemblance to garden-variety walleye or bass tackle. Siegel and his pals use rods 11 or 12 feet long, special dual-drag reels called bait runners, fish alarms to detect light bites and baits called “boilies” that are concocted mashes of grains and other boiled foods.

All this gear can cost a king’s ransom, although Siegel prefers less expensive gear.

“I’m probably the least sophisticated of our trio here today,” he said. “We all use the long rods, and 11 to 12 feet is typical of what we’d call a Euro-style carp rod. You can get to $1,000 in gear pretty quick. But you don’t need that. You can catch carp on a regular rod and a dough ball.”

Siegel wore a shirt with a picture of carp and the words, “Club Carp. Excitement. Romance. Live Bait.” He makes 50 or more carp fishing trips a year and belongs to an elite club: he has caught an elusive 40-pounder. (That was last year in Lake Michigan.)

That fish was released, as are all of Siegel’s carp.

“When I was a smallmouth fisherman, I was all catch-and-release,” he said. “I thought, I might as well go after the hardest-fighting fish because I’m going to release it anyway.”

Being a rough fish, common carp don’t get much respect from anglers and often are blamed for ruining water quality, because they root in the mud for food and for outcompeting other game fish for food.

But carp anglers such as Siegel view carp as a fish worthy of praise, and thus none are ever killed.

“I really object to people throwing them up on shore and leaving them,” Siegel said.

“Gardens,” piped up Collins. “I hate it when people just throw them in gardens.”

“Me, too,” Siegel said.

A distinction should be made. Common carp are not viewed as dangerous to the environment as are newly arrived exotics such as grass carp and Asian carp. Common carp are ubiquitous and can reach sizes in excess of 50 pounds.

For the most part, die-hard carp anglers never eat carp. Contaminants are a problem because they collect in the flesh of the bottom-feeders, but most carpers follow a strict catch-and-release ethic.

During their outing, Siegel and his friends had plenty of opportunities to release their favorite fish.

When Collins’ fish alarms sounded, he hauled back on the 12-foot rod and set the hook on a large fish. But, after a few moments, his line fell limp.

“What happened?” Moran said.

“Broke my line.”

Collins’ bite alarm is attached to his rod and worked by threading the fishing line through a small hole in the electronic device. The alarm sounds when the line moves. Being a wary fish, carp tend to need time to pick up bait and keep it in their mouth. In most instances, the anglers let the fish “run” with the bait before setting the hook. Hearing the alarm is the first step in that sequence.

“When you have a lot of carp fishermen around, the alarms can sound like a symphony,” Siegel said.