Thursday, February 8, 2007 Older Editions

Swimming with guppies

By April Guilmet

New Doherty Middle School teacher Thomas Desjardins said he's always looking for new ways to get students "hooked" on science. That explains the 10 small fish tanks circling his classroom.

These fish aren't pets. They are meant to help Desjardins, a Danvers transplant, tackle the daunting task of teaching genetics to eighth-graders. When Desjardins was awarded a Peggy Corbett science grant last month, he headed straight for the pet store.

"It's not a very easy subject to teach," Desjardins laughed. "So I came out with Guppy Genetics. Right now we're in the first phases of the program."

The class is raising guppies, which are ideal for the project because they tend to multiply quickly, Desjardins said. Each tank is identical in size, temperature, filtration and chemical balance, he said.

The only difference is that each tank has its own combinations of guppy colors and species.

Vibrant paper guppies drawn by students Elaine Wu and Liz Gosselin hang on the walls.

"The fish are teaching us biology," said Elizabeth Doherty, 13, a student in Desjardins's class.

"And organization is the key to success. At least that's what he's always telling us," she laughed.

With the project in its early stages, the tanks aren't brimming with fish quite yet. But Desjardins hopes they will be by the end of the school year.

"I'd always wanted to try this, but I wasn't familiar with the fish," he said.

With each tank costing about $100, he's hoping to find funds to purchase four or five more. He said he'd also welcome donations of fish tanks or aquarium gear that residents might have cluttering their basements.

What are some of the challenges that have come up so far? Well, the parenting skills of guppies leaves a lot to be desired. "The moms eat the baby guppies," said Tommy Shannon, 13.

Finding proper pH balance in the town's water can also be tough, he added.

As he siphoned waste from one tank's bottom, Ben Cook, 13, agreed that raising fish isn't always easy. Because the school turns down its heat on weekends, it can be difficult to keep the guppies' water warm.

"Last weekend some of the tanks got down to 60 degrees. Another one was 110 degrees," Ben said.

Right now, all of the tanks are kept at a consistent 80 degrees.

Each of 25 students in Desjardins' marine biology class help care for the fish.

"Once they got used to the idea of getting their hands wet and dirty, they had fun with it," Desjardins said.

Desjardins emphasized the importance of the upcoming MCAS tests, adding that the students are learning aspects of chemistry as well as genetics by tending to the tanks.

"This stuff will be covered," he said. "It's a true scientific experiment we're doing, complete with controls and variables."

When summer comes, he hopes he can give fish to his students to take home.

"It will be a nice reminder of the class for them," Desjardins said.