Dog is getting aggressive?

My 3 yr old dog, Roscoe, has become very aggressive toward my other dog, Toby, around food and toys and treats. He has attacked him multiple times in the past, twice today. Roscoe always wants what Toby has and Roscoe is always the aggressor. I don't know what to do anymore. I stopped buying the rawhides they were originally fighting over but now it has turned into everything else. I have a baby coming soon and can't have 2 dogs fighting around the baby. Help please.