Fish accepting right channel (6)
I believe the answer is:
trench
'channel' is the definition.
(I've seen this in another clue)
'fish accepting right' is the wordplay.
I cannot really understand how this works, but
'right' could be 'r' (common abbreviation) and 'r' is located in the answer.
'fish' could be 'tench' (tench is a kind of fish) and 'tench' is present in the leftover letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for trench that I've seen before include "A deep ditch, as dug for troops" , "Deeply cut" , "A ditch dug by soldiers" , "Ditch dug as fortification" , "Long, narrow excavation" .)