The Supreme Court's rescue of the little snail darter fish from federal dam builders has set off a sort of "pork panic" in Congress.

Legislators who fear further use of the Endangered Species Act of 1973 to stop pet public-works projects in their districts are pushing to weaken the law, which is due to expire Sept. 30.

The popular caricature of a useless but imperiled rare fish stopping an expensive dam in Tennessee-the court's Tellico decision-has fueled the rush to make the law "more flexible."

Just days after the court ruling, the House provided a new appropriation to complete the Tellico Dam and flood out the small darter.

Critics, notably Rep. Ted Risenhoover (D-Okla.), are painting the Endangered Species Act as an affront and a menaco to-man, a parody of the democratic process.

"I would rather see nature lose species than for our people to lose their rights to decide their own destiny," Risenhoover said last week.

Other critics are depicting the act as a toy for no-growth advocates and power-happy bureaucrats woh would use it to halt dams, roads and other developments.

But the irony of this debate in Congress is that, of the hundreds of federal projects already touched by the act, the Tennessee Valley Authority's Tellico Dam-the area where the snail darter swims-is the only one ever stopped.

Adding to the irony: Despite the popular notion that the $120 million project is lost, TVA is working on an alternative plan tha board chairman S. David Freeman says may provide even more benefit to taxpayers.

The Supreme Court held tha TVA could not go ahead with the project as planned, even though the dam is nearly compelted, because the agency had failed to comply with the Endagered Species Act.

Freeman's assurances have not done much to calm the panic around the House. The Tellico case has helped set the stage for one of those textbook confrontations: the builder'developer against the conservationist.

At this point, the builder-developer appears to be winning. Environmentalists and the Carter administration, which oppose changes in the law, concede that the mood is such on Capitol Hill that amendments seem inevitable.

In the vein of irony, and even before Tellico became the first project stopped, the Senate Environment and Punlic Works Committee adopted and amendment to set up a new review procedure for threatened projects.

Sponsored by Sen. John C. Culver (D-Iowa) and Howard H. Baker Jr. (R-Tenn.), it would create a Cabinet-level review commission-that is politicians-to resolve the impasses seen developing.

But underlying that runs another theme-that the Tellico case will spur environmental groups to mount a frontal assault on the public-works treasure trove.

Liz Kaplan of Friends of the Earth, coordinator of the antiamendment forces, put it this way: "This act system . . . Fear of the future is the problem and we can't seem to counteracct it."

Keith Shriner, associate director of the Interior Department's Fish and Wildlife Service, which aministers the act, added:

"It is a total fear of the unknown and the idea that all this power is given to bureaucrats. This is th best piece of conservation law ever written at any time, any place in the world. You don't know how bad it feels to see it threatened."

But the threat, as seen by legislators such as Risenhoover, John J. Duncan (R-Tenn.), Robin Beard (R-Tenn), Wesley W. Watkins (D-Okla.) and John Buchanan (R-Ala.), is to society rather than the animal world.

"The rights of the governed are perishing from the earth and the most endangered species may be the independent-minded American," Risenhoover said last week. "The country is just lucky the original legislation specifically forbids the listing of insects as endangered species."

At stake in Oklahoma-in the area represented by Watkins and Risenhoover-may be the Army Corps of Engineer's Lukfata dam and lake project.

The Fish and Wildlife Service has made no formal ruling, but it says the endangered leopard darter fish may create some problems at Lukfata.

The problems could be for the leopard darter or they could be for the engineers. But the law is designed to work out commodations to protect imperiled animals and plants and their habitats, yet allow projects to go ahead.

"The essence of it," said Shriner, "is not to stop important projects, but to save ecosystems. It is working. We have implemented the act with prudence."

Rep. Richard L. Ottinger (D-N.Y.), a defender of the act, puts it in another light: "The act is a tool by which we have agreed to preserve the great biological diversity of our natural heritage for future generations."

According to Interior, hundreds of accomodations have been reached under the act's consultation process, allowing a project to go ahead while protecting a species or its habitat.

"The essence of the act is not to stop important projects, but to save ecosystems," said Shriner. "It is working. We think we have implemented it with prudence."