Which Omegas for my 4 year old?

My daughter started school last sept and has been sooooo tired ever since. The poor thing is running on empty. She is young in her year (end of july baby) which doesnt help. She goes to bed (and straight to sleep) by 6 or 6.30pm every night and gets up anytime from 6.30am. And I try to get as much good food into her as i can. Someone has suggested that I try giving her omegas. I dont know anything about these. My daughter doesnt eat fish which i think is Omega 3?

Will these supplements help with her energy and moods?? Which ones should I be looking for? Just Omega 3??

She has a supermarket brand multi vit every day and I sometimes giver her kids echinasea (sp?).

Thank you!