I assume that during Gollum’s ownership of the one ring, the ringwraiths felt a constant desire for fish that none of them understood
“… I sssssssuddenly want sssssssome—”
“Fisssshhh?”
“Me, too. What ssssssssay we go down the chippie?”
“Who paysssssssss? Sssssssshhit, why are you all looking at me?”