I think it is only the white (beige) ones that are algae. The others are all vegetable based. I remember trying all of them and Charlie wouldn't eat the white/beige ones.
Amazon answers (scroll down) lists the ingredients
https://www.amazon.co.uk/Antos-Mixed...ds=Antos+chews
You used to be able to buy packs of four mini ones and I think the algae white/beige ones were sold separately. I only ever get the mini ones - they're a good size for a hamster.