Fish with doctor in cold area (6)
I believe the answer is:
tundra
'cold area' is the definition.
'tundra' can be an answer for 'area' (I have seen 'Area of permafrost' mean 'tundra' so perhaps 'area' could also mean 'tundra'). I am not sure about the 'cold' bit.
'fish with doctor' is the wordplay.
'fish' becomes 'tuna' (tuna is a type of fish).
'with' indicates putting letters inside.
'doctor' becomes 'Dr' (abbreviation).
'tuna' going around 'dr' is 'TUNDRA'.
'in' is the link.
Can you help me to learn more?
(Other definitions for tundra that I've seen before include "Area of permafrost" , "Northern permafrost region" , "Vast treeless plain in the arctic regions" , "Treeless Arctic region" , "Treeless northern region" .)