Wet fish stores quite popular (5)
I believe the answer is:
rainy
'wet' is the definition.
('rainy' can be similar in meaning to 'wet')
'fish stores quite popular' is the wordplay.
'fish' becomes 'ray' (ray is a kind of fish).
'stores' indicates putting letters inside.
'quite popular' becomes 'in'.
'ray' placed around 'in' is 'RAINY'.
(Other definitions for rainy that I've seen before include "(Of weather) wet" , "With water falling outside" , "Pluvial" , "Drizzly" , "Save your money for a . . . . . day - to buy an umbrella?" .)