Benjamin Franklin said that fish and guests stink after three days, but then he never met Peter Falcione, 39, of Norwalk, Conn. At Falcione's Norwalk Aquarium Fish Hotel, the guests are fish and, he says wryly, strictly up scale—"the kind that come from private schools. Most are quiet and well behaved. They don't steal towels."

So far as Falcione knows, his is the only hostelry of its type in America, and it evolved more out of accommodation than intent. "Every aquarium takes in fish for special customers," he explains, "but I found I had so many that my selling space was restricted. So I started the hotel in 1978."

His guests are checked in because their owners are away or because of house painting (the fumes can be fatal to sensitive tropical fish). Among his more unusual boarders have been a two-foot nurse shark whose aquarium was under repair and a free-spirited octopus whose owner feared it might climb out of its home tank while she was out of town.

Weekly rates on the American plan (two feedings daily) start, aptly, at a fin ($5) for 10-gallon accommodations and run up to $60 for the spacious (55 gallons) Neptune Suite, complete with complimentary coral. Reservations are required at the 32-unit hotel; major credit cards are accepted. "If a guest's bill is overdue," deadpans the innkeeper, "we sell him."

Falcione, whose mother ran a tropical-fish store in Philadelphia, attended Temple University and worked as a salesman before he and his wife, Patricia, moved to Norwalk in 1964 and bought the aquarium store five years later. The fish hotel, he concedes, is not a big money-maker, though bookings doubled in the past year.

Hotel amenities include custom matching of water with a guest's home aquarium and an around-the-clock temperature-monitoring system. Delicacies include a high-protein menu of worms and brine shrimp or a health-food diet of plants. Guests almost always check out healthy. "We've only lost two," Falcione says, "and both were inexpensive fish, so I replaced them. And," he adds with a conspiratorial wink, "their owners didn't even know."