It doesn't seem to be anything other than omega 3 but in a more concentrated form,
from an article in the Daily Mail
"A month’s supply of 30, 1,000mg Calamari Gold capsules costs £34.99 from Holland and Barrett. An equivalent supply of cod liver oil capsules costs around £2.25."
Or £3.50 for 90 tablets at Asda, I think I'll stick with the Asda ones (other supermarkets are available).
K