Howlong fever for a one year baby is okay?

Depends. Depends on how high the fever is, how responsive the child is and what is causing the fever. If it is a low-grade temp, should be ok, if it is persistently 101 or higher for over an hour with no relief from tyleno;, I would certainly call the pediatrician. If the child is also more lethargic or poorly responsive I would take the child to the ED immediately.