As we process applications for the 2010 Inc. 500 | 5000, we thought it would be worthwhile to shine a spotlight on some of the companies that are vying to appear on our ranking of the fastest-growing private companies in the U.S. One that caught our eye was San Francisco-based CleanFish.

Farm fishing doesn't exactly have a great reputation for quality, or for environmental friendliness.

In 2004, Tim O'Shea set out to change that. The lifelong eco-entrepreneur partnered with seafood industry veteran Dale Sims to found CleanFish, a San Francisco-based company which partners with non-industrial "artisan" fisheries, as O'Shea calls them, that are committed to sustainable practices, and sells their products to distributors, restaurants and supermarkets.

"On one hand we're just a broker, because we buy and sell fish, but we are much more selective in vetting and sourcing our fish," says O'Shea, who is CEO of the company. "You don't need a marine biology degree to taste a piece of fish and know that it tastes good. At the same time, these industrial scale practices are destroying habitats."

The business plan wasn't met without skeptics, especially in an industry dominated by commercial fisheries. "When we said we were going to focus on smaller, sustainable seafood producers, it was mostly a roll of the eyes response," O'Shea says. But over the past three years, revenue grew more than 250 percent to $18.2 million. "It's very clear this is what the market is looking for," he says.

CleanFish products, which range from Icelandic Arctic Char to Peruvian Blue Tilapia, aren't limited to aquaculture. Its 33 suppliers also include local wild-caught sustainable fisheries. These fisheries previously found it difficult to compete with larger commercial fisheries, but CleanFish recognizes their commitment to better practices and pays a premium for it.

The CleanFish products are now in 45 states as well as Canada, including the kitchens of renowned chefs like Eric Ripert and Thomas Keller. O'Shea says that this year, they'll begin expanding internationally, to Europe, and focus on finding more producers.

"It's a major change in the marketplace," O'Shea says. "This is a brand not interested in beating down the sources of [quality] fish production, but lifting them up, getting them better pricing, and building a brand around that."