Fellow eating very soft fish (5)
I believe the answer is:
guppy
'fish' is the definition.
(I've seen this before)
'fellow eating very soft' is the wordplay.
'fellow' becomes 'guy' (I've seen this before).
'eating' is an insertion indicator.
'very soft' becomes 'pp' (**).
'guy' enclosing 'pp' is 'GUPPY'.
(Other definitions for guppy that I've seen before include "Tank occupant" , "Small bright WI fish" , "Small fish of northern South America and the Caribbean" , "Aquarium fish" , "Tropical fish" .)