Such a tide does not suit all guinea pigs (4)
I believe the answer is:
neap
'such a tide' is the definition.
(neap tide is a kind of tide)
'not suit all guinea pigs' is the wordplay.
'NEAP' is hidden within the letters.
However, I'm unsure how the hidden word is indicated.
'does' acts as a link.
Can you help me to learn more?
(Other definitions for neap that I've seen before include "A less than average tide" , "Sort of tide" , "Small tide" , "The half-way kind of tide" , "Tide of smallest rise and fall" .)