Fish that’s set before me in scales, so to speak (3)
I believe the answer is:
ray
'fish' is the definition.
(I know that ray is a type of fish)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for ray that I've seen before include "Flatfish or sunbeam" , "Gleam" , "Shaft of light" , "Pencil of light" , "Beam of light or flat fish" .)