Tanks in shade getting fresh air (7)
I believe the answer is:
aquaria
'tanks' is the definition.
(aquarium is a kind of tank)
'shade getting fresh air' is the wordplay.
'shade' becomes 'aqua' (I've seen this before).
'getting' means one lot of letters goes inside another.
'fresh' indicates an anagram (a fresh re-ordering of the letters).
'air' anagrammed gives 'ari'.
'aqua' enclosing 'ari' is 'AQUARIA'.
'in' is the link.
(Other definitions for aquaria that I've seen before include "display tanks" , "Tanks or buildings for fish" , "Transparent fish tanks" .)