The use of fish in love-charms resurfaces 900 years later and is printed in Migne's PL 140 as part of the "Decreta" of Burchard of Worms:

Fecisti quod quaedam mulieres facere solent? Tollunt piscem vivum, et mittunt eum in puerperium ["childbed" -- perhaps literally of an empty bed the woman wants to fill?] suum, et tam diu eum ibi tenent, donec mortuus fuerit, et, decocto ["boiled"] pisce vel assato ["cooked/roasted"], maritis suis ad comedendum tradunt, ideo faciunt hoc, ut plus in amorem earum exardescant? Si fecisti, duos annos per legitimas ferias poeniteas.

I regret having misplaced the name of the colleague who pointed out this reference to me -- Jim O'Donnell (8/24/2000)