I haven't been here in a long time, but I'm having an issue I don't quite know how to deal with. I have two brothers, fifteen months old. When they were younger, Oskar was the big, tough, brave one whereas Vinzent was small, timid, and afraid of most things, always hiding behind Oskar to protect himself. I always figured if I had any type of aggression issue, it would be with Oskar, but lately Vinzent has become very greedy and aggressive around food. It started a couple of months ago. He began becoming very grabby (he would scratch up my hands trying to grab whatever I was holding,) and he would try to steal food right out of Oskar's mouth if Oskar didn't move somewhere else (which he now does.) Vinzent has hoarded food his whole life, but he was never aggressive about it in any way. Then last night, he bit me. I was putting their supper blocks into the cage. I gave Vin his blocks, then while I was giving Oskar his own blocks, Vin ran across the cage, bit me hard on the back of my hand, then ran away. I grabbed him and pinned him; I didn't really know what else to do, that's the first time I've ever gotten more than a play-bite from any of my rats. Just now, a big fight broke out between the two. I never saw it start, but there was still half eaten food in the area they were fighting, so I suspect that Oskar must have wandered too close to Vin while he was eating. Vin seems to forget though that his brother is still bigger and stronger than him, and he lost (another) rear toenail in the process. Right now they're separated while Vin's toe stops bleeding, but I'm not sure what to do. The aggression isn't all the time, it's ONLY around food, and I was under the impression that the period for them to suddenly become aggressive and require neutering was at a younger age. They eat fine, they each get six blocks of food (Extrusion) a day as well as two servings of vegetables, and potentially other fruits or veggies or healthy yummies the family may happen to cook during the day. I weigh them once a week and although they both lost weight this winter (which was on purpose, they were both overweight,) Vin has peeked out at 475g and stayed there for a few months now (he's always been a small rat.) I'd like to think maybe Vin will learn from this experience and stop being a brat, but I don't think rats really think that way. The only (and obvious) excuse is that Vin isn't reacting well to being fed certain amounts of food at certain times of the day (as opposed to before when they were free-fed and their bowl was just always full.) If that is the case, and the only way I can fix this is by going back to free-feeding, is it worth letting them both potentially become overweight again to stop the fighting?