Raw treat prepared for amphibious creature (5,3)

I believe the answer is:
water rat
'amphibious creature' is the definition.
'water rat' can be an answer for 'creature' (water rat is a kind of animal). I'm not sure about the 'amphibious' bit.
'raw treat prepared' is the wordplay.
'prepared' indicates anagramming the letters.
'raw'+'treat'='rawtreat'
'rawtreat' is an anagram of 'WATER RAT'.
'for' is the link.
Can you help me to learn more?
(Other definitions for water rat that I've seen before include "Endangered vole" , "Small amphibious rodent" , "Vole of the 17" , "Beast" , "Swimming rodent" .)
