A Queen song about upper-class homes for goldfish? (7)
I believe the answer is:
aquaria
'homes for goldfish?' is the definition.
(plural of aquarium)
'a queen song about upper-class' is the wordplay.
'queen' becomes 'q' (chess abbreviation).
'song' becomes 'aria' (aria is a kind of song).
'about' says to put letters next to each other.
'upper-class' becomes 'u' (similar in meaning).
'aria' after 'u' is 'uaria'.
'a'+'q'+'uaria'='AQUARIA'
(Other definitions for aquaria that I've seen before include "Transparent fish tanks" , "Tanks or buildings for fish" , "display tanks" .)