Fish, net and deck (7)
I believe the answer is:
garland
'deck' is the definition.
(I've seen this before)
'fish net' is the wordplay.
'fish' becomes 'gar' (type of gar).
'net' becomes 'land' (both can mean to secure or obtain).
'gar'+'land'='GARLAND'
'and' acts as a link.
(Other definitions for garland that I've seen before include "Judy . . . . . . . who played Dorothy in The Wizard of Oz" , "Blooming prize" , "Floral wreath" , "Flower wreath" , "Floral tribute" .)