Fish found in overturned waterproof sheets (5)
I believe the answer is:
sprat
'fish' is the definition.
(sprat is a kind of fish)
'overturned waterproof sheets' is the wordplay.
'overturned' shows that the letters should be reversed in order.
'waterproof sheets' becomes 'tarps' (I've seen this in another clue).
'tarps' reversed gives 'SPRAT'.
'found in' is the link.
(Other definitions for sprat that I've seen before include "Small herring, often smoked or canned" , "Small herring-type fish" , "Small fish, sardine, say" , "Small herring-like fish" , "It may catch a mackerel" .)