Thank you for your reply.
He's 10 months old. Born Oct last year so we named him Pumpkin.
Not sure about coccidia... But I read another forum post and their goose may have had mycolotoxins, with similar symptoms.
(With lots of research online) we decided to give the antibiotics yesterday...
My goose has not been eating for almost 4 days.
He drinks water and I've managed to get him to drink some vitamins.
He's a bit more slow in walking and sleeps more often.
He still follows his gander around and I've seen them mating two or three times in the past few days.
He still bathes...