The poor fish that does so is apt to get caught (5)
I believe the answer is:
rises
'apt to get caught' is the definition.
I can't judge whether this definition defines the answer.
'the poor fish that does so is' is the wordplay.
I cannot really see how this works, but
'is' is present in the answer.
The remaining letters 'res' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for rises that I've seen before include "Moves upwards" , "Gets up" , "Ascends" , "Moves upward" , "Comes or goes upward" .)