With royal in South Africa, eat fish (7)
I believe the answer is:
sardine
'fish' is the definition.
(sardine is a type of fish)
'with royal in south africa eat' is the wordplay.
'with royal' becomes 'r' (abbreviation. I am not sure about the 'with' bit.).
'in' means one lot of letters goes inside another.
'south africa' becomes 'SA' (abbreviation).
'eat' becomes 'dine' (to dine is to eat a meal).
'sa'+'dine'='sadine'
'r' inserted within 'sadine' is 'SARDINE'.
Can you help me to learn more?
(Other definitions for sardine that I've seen before include "Stonefish OR? Stone" , "A diner's small fish" , "Fish (often tinned)" , "FRENCH FISH" , "Young pilchard" .)