It's edible, but for its tail (7)

I believe the answer is:

halibut

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'its tail' is the definition.
I can't tell whether this defines the answer.

'it's edible but' is the wordplay.
'it's edible' becomes 'hali' (I am not sure about this - if you are sure you should believe this answer much more).
'hali'+'but'='HALIBUT'

'for' is the link.

Can you help me to learn more?

(Other definitions for halibut that I've seen before include "Something fishy here" , "Large flatfish used as food" , "Fish found in Bali hut" , "Utah lib (anag)" , "Marine food fish" .)

I've seen this clue in the Evening Standard.

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