When I was younger and not yet living in France, I discovered a small hotel on the Dordogne river (Hotel du Pont in Groléjac) that served a wonderful fry of small fish. It was called “petit friture” which has the same double meaning as “small fry” in English as it means both fish and frying. There they used goujon, small river fish.
In the Paris area I sometimes bought éperlan, sprat, to fry. This came from the Atlantic.
Here in the Ariège, where most fish comes from the Mediterranean, they sell Jol, also called Joël or Athérine after its Latin name Atherina Boyeri. In English it is the large-scale sand smelt.