Middle Eastern country’s brought in a lot of excellent fish (7)
I believe the answer is:
piranha
'fish' is the definition.
(piranha is a kind of fish)
'middle eastern country's brought in a lot of excellent' is the wordplay.
'middle eastern country' becomes 'Iran' (country in the Middle East).
'brought' becomes 'ph' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'a lot of' means to remove the last letter (most of the word but not all of it).
'excellent' becomes 'ai' (resembles 'Ap', old-fashioned term for excellent).
'iran' inserted into 'ph' is 'piranh'.
'ai' with its final letter removed is 'a'.
'piranh'+'a'='PIRANHA'
Can you help me to learn more?
(Other definitions for piranha that I've seen before include "fish chewed up" , "Ferocious fish" , "Voracious river fish" , "Small voracious carnivorous fish" , "Small carnivorous freshwater fish" .)