Figure a companion to be a natural swimmer (5)
I believe the answer is:
tench
'a natural swimmer' is the definition.
'tench' can be an answer for 'swimmer' (tench is a kind of fish). I'm not certain of the 'a natural' bit.
'figure a companion' is the wordplay.
'figure' becomes 'ten' (ten is a number).
'a companion' becomes 'ch' (Companion of Honour).
'ten'+'ch'='TENCH'
'to be' acts as a link.
Can you help me to learn more?
(Other definitions for tench that I've seen before include "Coarse fish" , "catch" , "Swimmer" , "Fish of the carp family" , "Freshwater fish" .)