AquaBounty Technology received a federal funds to help sterilize genetically-modified fish that are able to grow year round.
The USDA awarded a $494,162 grant to ensure the modified salmon wouldn't reproduce with wild salmon.
The AquAdvantage salmon grow much more quickly than wild salmon. The fish appeared like it would be the first genetically modified animal approved for human consumption, but legislation has since stalled.
Current statements from AquaBounty state the fish is 99.8 percent sterile, but even a small number worries environmentalists.
"If the FDA was so assured of the scientific merits of this application, they would have approved it by now," analyst for the Center for Food Safety Colin O'Neil says.
U.S. lawmakers are concerned with "frankenfish" as well, leading states like Alaska to push for legislation banning genetically modified fish.