Okay so a week ago, I bought a fancy rat from Petsmart named Ratty (male). He was very sweet and loved being held (but not pet) and played with. Today I got another rat from Petco named Monic (male). He is a PEW (pink eyed white). I introduced the two and thought they would be fine since it said they would be fine on a few websites I looked on. I put them on a neutral area (my bed) and they were off to a bad start.... Monic started following Ratty trying to sniff him but Ratty didnt like that... Monic is very calm and didnt try to hurt Ratty..... But Ratty eventually started biting Monic... Not softly either. I know it was aggression because Monic shrieked and I got Ratty away from him.... I tried again about 30 minutes later.... I dont know what I was thinking... Ratty bit Monic as hard as he could and I had to pinch Rattys face without hurting him to get him to let go. I want my rats to get along because Monic seems to want to be social.... Im scared to try the vanilla approach because I dont want Monic to get attacked again by being with Ratty too soon. What can I do?