Model observed fish using ears (5)
I believe the answer is:
ideal
'model' is the definition.
(ideal can mean model or perfect)
'observed fish using ears' is the wordplay.
I cannot quite understand how this works, but
'fish' could be 'ide' (type of fish) and 'ide' is present in the answer.
The remaining letters 'al' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ideal that I've seen before include "unlikely to be bettered?" , "fine" , "Paradigm" , "superb specimen" , "The best conceivable" .)