Mussel habitat (5)
I believe the answer is:
shoal
(Other definitions for shoal that I've seen before include "Collection of fish" , "shallow water" , "Swarm of fish" , "Mob" , "Lots of fish" .)
I believe the answer is:
shoal
(Other definitions for shoal that I've seen before include "Collection of fish" , "shallow water" , "Swarm of fish" , "Mob" , "Lots of fish" .)