A pirhana fish in a tank near a new and rare albino alligator which has taken up residence with other scary fish just in time for Halloween at the National Aquarium on October, 05, 2011 in Washington, DC. (Bill O'Leary/WASHINGTON POST)

What’s a shark to do when it has lived in one tank for years, tucked inside a small museum, surrounded by its fellow species — a swell shark, a horn shark, a leopard shark and juvenile chain catsharks — and one day its keepers get notice that they have to get out? To find new waters, so to speak?

The National Aquarium — established in 1873 and tucked away in downtown’s Commerce Department building, erected in 1932 — announced Thursday that it will close its facility Sept. 30 because the building is being renovated.

The renovations mean the aquarium must move its collection of 250-plus species of 1,500 aquatic creatures — including toads, snakes and salamanders — to other accredited zoos and aquariums. Aquarium officials said that many of the animals will move to the National Aquarium in Baltimore, but some might have to find homes in zoos across the country.

It is unclear whether these new homes will be permanent, museum officials said. The aquarium received notice last month from the General Services Administration that it must move out of its space by next March. To provide for enough time to find places for the animals, its board of directors decided to close the aquarium in the fall.

Where the aquarium will relocate is undecided. Tamika Langley Tremaglio, a member of the aquarium’s board of directors, said of the notice to vacate: “This was something we were not aware of previously. . . . GSA and the Department of Commerce have been in conversations about renovations. The timeline, specifically, we weren’t aware of until recently.”

Tremaglio said the aquarium had worked on a plan to move within the building, but “the plan called for budget of about $50 million, which is currently not available in [the] public and private sector.”

John Racanelli, chief executive of the National Aquarium, said the museum recently opened discussions with the Smithsonian Institution about possible locations. “There has been a public aquarium in the capital since the 1880s,” Racanelli said. “It makes sense to continue that tradition. We are pursuing options to see whether we can do so.”

Kate Hendrickson, the aquarium’s spokeswoman, said the institution hopes to find a new location in the District. “We value being in the capital, in Washington, D.C.,” Hendrickson said. “But right now, we are not sure what the future is. A task force is pulling locations.” Hendrickson said a task force is exploring housing options for the aquatic animals.

“We use the term aquatic, but that doesn’t necessarily mean they live underwater,” Hendrickson said. “Most are either water-based or live near the water. . . . Those animals need specific habitat[s] — from saltwater versus fresh water or coral reef versus marshland.

“Whatever animals we can take to Baltimore and the off-site facility in Baltimore, we will,” Hendrickson added. “Whatever animals we can keep in the family and move to other facilities, we will. We are an Association of Zoos and Aquariums [institution] — we are accredited by them.”

The National Aquarium, one of the country’s first public aquariums, opened in 1885 “with a collection of 180 species of fish, reptiles and other aquatic animals.”

In 1982, when the National Aquarium Society was formed, the aquarium lost its federal funding and became a nonprofit organization. The aquarium, which draws more than 200,000 visitors annually, is supported by donations and admission fees, which range from $4.95 to $9.95.