My little boy has been doing this (vomitting yellow semi-transparent liquid) for 2 days now, too. I immediately contacted my vet and he said my Boogie has gastrich. He told me to feed him more than twice a day, only with smaller rations, but it doesn't help. Boogie still takes his Nutri-plus gel, though, and even though he looks hungry he still doesn't take his food.
I have stayed beside him all the time ever since he vomitted his first yellow liquid. I don't know what to do anymore, my vet has only been saying that I do what he told me. And I did, but it doesn't work. It. Doesn't. Work.
Edit: Anybody can recommend me a good medicine, or does he not need any?