Something fishy at Minneapolis' Gandhi Mahal? A basement tilapia farm!

A lush jungle of sorts has sprung up in a basement off Lake Street in Minneapolis, where tilapia are now swimming amid Minnesota's first aquaponics system based in a restaurant.

In a humid room beneath Gandhi Mahal restaurant, local officials watched Thursday as owner Ruhel Islam plunged his arm into a tank and threw a wriggling tilapia into a bucket of ice water. The waste from those 100 fish helps fertilize the surrounding beds of tomatoes, peppers, herbs, celery and spinach.

"Should I go for one more?" Islam asked the crowd, jammed into the 650-square-foot room.

Aquaponics is a growing business in the Twin Cities and across the country, but local operations are typically large-scale production facilities that sell to grocery stores and restaurants. One of the most prominent examples in the urban core is at the former Hamm's brewery in St. Paul, which is now filled with thousands of fish and plants.

Gandhi Mahal was already known for its sustainability efforts, which Islam says is a reflection of his native Bangladeshi culture. It harvested 10,000 pounds of vegetables last year from about a dozen back-yard gardens within 2 miles. Islam hopes to eventually build a greenhouse on the roof, expand the basement fish operation and possibly even raise chickens at a suburban farm.

"We are working toward our dream," Islam said. "One day we will become completely self-sufficient so that we can lead as an example."

The underground aquaponics system, a collaboration with the nonprofit organization Spark-Y, is a first for a restaurant in Minnesota, said Paula Phelps, aquaculture and fish health consultant at the Department of Natural Resources. The DNR oversees the restaurant's aquaculture license.

"This is the first aquaponics system in a restaurant that is basically basement to table," said Zachary Robinson, executive director of Spark-Y, which has designed 10 similar operations for classrooms across the metro area.

Following a ribbon-cutting, the tour moved to the kitchen where Islam smothered the fish in turmeric, garlic, salt, garam masala and lemon and pan-fried them.

The facility does not hold enough fish to make the in-house tilapia a staple menu item, but Islam says the staff plans to set aside several fish every month so customers can call ahead, reserve one and even help catch it. The tomatoes and greenery are already being used to make salad.

"I'm going to start small and show that we can really do it," Islam said. "That's very important toward food security."

So how does it work? Four species of tilapia — an extremely hardy freshwater fish — live in the 350-gallon tank, which is connected via PVC plumbing to the surrounding garden beds. The ammonia and waste they release eventually become nitrates, which are absorbed by the plants before the water runs back to the tank.

"The water is continually recycling, just like we find in nature," Robinson said. Small shrimp are growing in side tanks, so they can potentially become a sustainable fish food.

This type of operation wasn't legal until 2012, when the city changed its zoning code to allow commercial farming — including aquaponics — in Minneapolis.

"We didn't allow anybody to grow food for sale in the city," said Council Member Cam Gordon, who helped spearhead the change.

The city's health director, Dan Huff, said Gandhi Mahal is inspected like any other restaurant.

"They need to treat … the fish and plants they raise as if they purchased it from another approved source," using proper sanitation practices, Huff wrote in an e-mail.

Other restaurants in Minneapolis, including the Birchwood Cafe, Common Roots and Tiny Diner, have built a model around locally sourced food.

Kim Bartmann, who owns Tiny Diner, operates a south Minneapolis farm that supplies her suite of restaurants. She is exploring the idea of an aquaponics operation at her new Loring Park outpost, the Third Bird.

"Local and sustainable might be sounding like a cliché, but it's an imperative for our food security in the future for us to be able to produce more food in urban settings," Bartmann said.