Fish devouring fantastic bat -- suspect treachery? (5,1,3)
I believe the answer is:
smell a rat
'suspect treachery?' is the definition.
'smell a rat' can be an answer for 'suspect' (to smell a rat is to suspect something). I am not sure about the 'treachery?' bit.
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for smell a rat that I've seen before include "Suspect something wrong" , "Have suspicion something is afoot" , "Find something fishy" , "Sense something suspicious" , "Suspect deception" .)