Fish surprises, served with nut endlessly (4,6)
I believe the answer is:
rock salmon
'fish' is the definition.
(I know that rock salmon is a type of fish)
'surprises served with nut endlessly' is the wordplay.
'surprises' becomes 'rocks' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'served with' means one lot of letters go next to another.
'nut' becomes 'almond' (almond is a type of nut).
'endlessly' means to remove the last letter.
'almond' with its final letter removed is 'almon'.
'rocks'+'almon'='ROCK-SALMON'
Can you help me to learn more?
(Other definitions for rock salmon that I've seen before include "Catfish as food" , "Dogfish as food" , "swimmer" , "Fish" .)