Kipper's head and tail bad in seafood (5)
I believe the answer is:
krill
'seafood' is the definition.
(I've seen this before)
'kipper's head and tail bad' is the wordplay.
'head' indicates taking the first letters.
'and' says to put letters next to each other.
'tail bad' becomes 'rill' (I can't justify this - if you can you should give a lot more credence to this answer).
The initial letter of 'kippers' is 'k'.
'k'+'rill'='KRILL'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for krill that I've seen before include "seafood" , "What baleen whales eat" , "Whales' staple diet" , "Small shrimp-like creatures eaten by whales" , "Whale food" .)