Fish get into difficulties (8)
I believe the answer is:
flounder
I believe this clue is a double definition.
'fish' is the first definition.
(flounder is a kind of fish)
'get into difficulties' is the second definition.
(Other definitions for flounder that I've seen before include "fumble?" , "Struggle in water" , "Catch" , "Struggle clumsily - flatfish" , "Flatfish - behave awkwardly" .)