How to know, for example, that poor water quality or circulation in a tank and not a bacterial infection is making a fish sluggish?

"It's a combination of art and science," the 35-year old Kebus says of his profession.

At 6 foot 4, with a boyish face, Kebus looks more like an overgrown teenager than a medical doctor But as one of a handful of veterinarians in the country that specialize exclusively in fish, Kebus has a growing list of clients around the upper Midwest who call on him for his prowess in piscine health. He treats everything from 95-cent minnows to $1,200 ornamental koi. lie's a healer to commercial fish that comprise the state's $40 million aquaculture industry. He speeds to the rescue of an ailing goldfish and helps pet stores maintain healthy fish stocks.

"People like to joke that I carry my bag around and visit sick goldfish," he says. "It's true. But the scope of the fish industry in this region is pretty significant'

The Michigan native did his undergraduate work in Fast Lansing and in Surrey, London. At UW-Madison, he simultaneously earned his veterinary degree and a master's degree in aquaculture. In between his years at vet school, Kebus worked on a catfish farm in Mississippi, for the salmon industry in British Columbia, and studied at Woods Hole, Mass.

After graduating, Kebus worked in a small animal clinic for a year and in 1993, setup his private practice, Wisconsin Aquatic Veterinary Services, or WAVS for short. (He insists the acronym was accidental.) Kebus works mainly out of his truck, making house calls in a red Toyota Tacoma. A large, gray tackle box holds his medical instruments and supplies, consisting of such things as syringes, antibiotics (for pet fish only), chemical anesthesia, forceps, scalpels and scissors.

When called to the scene, Kebus evaluates a tank's PH, temperature and circulation and checks for possible contaminants. Such problems frequently plague home aquariums. To limit losses in the commercial industry, Kebus often must perform a necropsy, studying a fish's organs, body fat or gill conditions. Rarely does that solution require drugs.

"In three years I've never had one time where I've had to use antibiotics," he says. "I'm very conservative about introducing a chemical into a product that people are going to consume."

Still, Kebus's profession can be disarming. After he and his wife bought a new house, one of his former patients showed up dead, wrapped in plastic on the doorstep of his former residence. The new homeowner was alarmed to find the stingray on her stoop.

"After that I vowed to work on a house call only basis," Kebus says.