Every summer, the carnival rolls into town for Teton County Fair, and unsuspecting families become pet owners.

“We get a rush of people carrying their plastic bags into the store,” Gloria Courser, Rally’s Pet Garage owner, said. “‘What do I do? I have this fish!’”

Often, a child will go to the carnival with friends and return home, coveted prize in hand, she said.

“Parents are rolling their eyes,” Courser said. “Oh, great, a free fish, and now $50 worth of supplies. We’re parents, too; we’ve been there, done that.”

In preparation for the fair, Rally’s stocked 10 different varieties of fish housing, from a cheap plastic bowl to nice aquariums. They all sold. Within the first three days, the store ran out of goldfish food.

Celia Ward has a knack for carnival games, said her mom, Margaret Gordon. The 5-year-old won a stuffed turtle with a well-placed dart and garnered two goldfish by tossing pingpong balls into fish bowls.

“Given her track record,” Gordon said, “I wasn’t about to let her play the bunny game.”

Now the fish, which Celia named Splash 1 and Splash 2, are home in the Cottonwood subdivision in a fancy round tank. They’re swimming in circles and seem happy, although Celia and her sister, Lucia, 2, don’t remember to feed them, Gordon said. That may be just as well.

“I’ve heard of fair goldfish living for years,” Gordon said. “I hope we don’t have to upgrade tanks. I’m feeding them sparingly.”

Courser says the durability of the carnival fish are “hit or miss.” Her daughter, Lily Lonneker, 9, still has two goldfish from the 2011 fair, but two of the four she came home with this year have died.

The pet shop owner’s advice is to only feed goldfish every three days and only as many flakes as the fish will eat right away. That’s not just for the health of the fish but also for easy tank maintenance.

“What goes in comes right back out,” Courser said. “It makes for a disgusting tank.”

Bella Wood, 14, has wanted a turtle ever since she was a child reading Kay Thompson’s series of “Eloise” books. When she and her friend, Gabe Walls, were walking down the midway at Teton County Fair, they spied tiny red-eared sliders being offered as prizes.

Gabe, also 14, offered to win Bella a turtle, and he did. Her parents were not enthused. They had never had an amphibian before and had no idea what to feed it or how to care for it. The turtle was agitated, climbing the walls of the plastic container he came in.

“The level of innocence,” Libby Crews Wood said, “and ignorance on what it takes to care for them properly is high. These kids had no idea as they were standing there playing that game.”

Fortunately, the Woods knew another turtle owner, Laurel Wicks, who lent them a tabletop tank and gave them some aquatic plants that turtles like to eat. Now Raisin, as the turtle is called, has a proper home and seems more placid. Bella carries the tank out to their deck each day so Raisin can bask in the midday sun.

But tiny turtles shouldn’t be midway prizes, the Woods say, not just because kids will be ill-prepared to care for them. Selling or giving away turtles with a shell that measures less than 4 inches is against a federal regulation, enacted in 1975 to curtail the spread of salmonella. The Woods are cautious to always wash their hands after handling Raisin.

The cost of buying turtle accoutrements is significant, Libby Crews Wood said, since the aquatic plants they prefer aren’t sold nearby. And that’s just the start of it.

“He’s going to need more space,” Wood said. “He’s going to need sun this winter. He’s going to need a virtual tropical habitat. That little $2 ticket becomes quite the investment.”

Still, with no other pet in the household, Raisin is adding interest as well as responsibility. His cold-blooded charm seems to be catching.

Peter Wood, Bella’s father, has taken to playing the ukulele for the turtle. Apparently turtles have keen eyesight and hearing, Bella said.

Bella said she wishes Raisin would stay small forever.

“You should stay tiny and cute,” she said, hoisting the silver-dollar-size turtle in the air.

“Wrong attitude, Bella,” her father said, reminding her that turtles can live for decades and reach considerable size, up to 12 inches across.

“If all goes well, you’ll still be caring for him when you’re 50,” he said.