What does the cryptic crossword clue "What's clearly smelt with head cut off, or another fish (5)" mean?

The definition is "another fish". The wordplay uses a deletion. TENCH (deletion) = TENCH; definition: "another fish" The answer is TENCH.

What's clearly smelt with head cut off, or another fish (5)

Times Cryptic #28651 | 7 Down | 2023-07-10 flower