Roost (5)
'roost' is the definition.
(synonyms)
This is all the clue.
(Other definitions for perch that I've seen before include "What angler may catch" , "Bird's seat - fish" , "Freshwater game fish" , "Fish; pole" , "[SOMETHING FISHY]" .)
(Another definition for perca that I've seen is " genus of fishes".)
'roost' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for nest that I've seen before include "In which to lay eggs or give birth" , "A set (of tables)" , "Snug retreat" , "Shelter in which to lay eggs" , "Casually thrown" .)