Keep it just as a treat!  Yes, some love it.  Our Meetetsee used to.
There have been some fitch farms with Nutritional Steatis (Yellow Fat
Disease) from using squid as a major component of the diet.  You can
read more in _Biology and Diseases of the Ferret_ or in a recent FML
post, or in http://fhl.sonic-weasel.org
 
As an occasional treat it will be fine, except you will have the same
problem I had: less for yourself.  (Wolfy and I share a penchant for
mollusks.  Yum!  Steamers!  Thai Squid in Black Pepper Sauce!  Fried
Calimari with Lemon!  Escargot!  Broiled Bay Scallops with a bit of
butter!  Oyster chowder!  Mussels in a white wine broth!  Have to
stop... Making myself hungry...)
 
Wolfy adds:
>"Dippy give me that back!  Nonoitsabadferretno!!  Sukie says this is
>bad for you.  Give it.  Giiiive it, give it,give .......... it.  I know
>you like yellow, but this won't turn you yellow it's not good for you.
>Wow these things can really stretch.  Whats that popping noise?  Oh,
>eeew its the suckers."
 
ROFLOL!  Silly Wolfy!  A little bit now or then won't hurt at all, but
I'll bet Dippy LOVED playing keep away and tug of war with it.  You'll
have to see if she expects a game every time now!  Talks about a special
food!  It gets to be a rare treat AND play!  Boy, you are EASY for a
ferret to train, Wolfy!  Hey, my mouth is open, too!  I am licking my
chops!  I am willing to play tug of war!  Throw me one of those mollusks!
[Posted in FML issue 4809]