/sheet"fish'/ , n. , pl. sheatfishes , ( esp. collectively ) sheatfish .
a large, freshwater catfish, Silurus glanis, inhabiting rivers in central and eastern Europe, sometimes reaching a weight of 400 lb. (181.4 kg).
[ 1580-90; earlier sheath-fish; sheath is erroneous trans. of G Scheide sheatfish ]