I bought this delicacy from my fishmonger. He said they were "Cristardelle" (I made sure of the spelling). They look like small, well, swordfish-- complete with beak-- about 10 inches long and 1-2 inches in diameter.
He said that he'll "never get (as in 'find') them again" and that they are like smelt-- but better.
I googled "Cristardelle", but came up with… nothing. We're probably not spelling it right. Nevertheless, any info is appreciated. Thanks very much.