Will neutering a year old tomcat stop some of the aggressive behavior toward my other cats?

Getting him neutered will almost certainly tone down his aggressive behavior, especially if it's directed at other males. It's important to remember that testosterone remains in the body for up to several weeks after neutering so it won't be an overnight change. After neutering, confine him to a room for a couple days to let him recover from the anesthesia and surgery. It will still be important to introduce these cats to each other slowly and with lots of postive reinforcement (i.e. petting the cats and feeding them treats when they are in the presence of each other). Also make sure that your home has enough territory for six cats -- trying to make six cats live together in an efficiency probably won't work no matter how hard you try. Increase their territory by providing more vertical spaces for the cats such as cat trees and don't leave these cats alone together until you're absolutely certain they get along.

It will probably help quite a bit, but may or may not take the behavior completely away. It would then depend on the actual "catinality" - as I like to call it - of that particular cat. I have both of mine neutered, but the one is still VERY dominant. He isn't as mean anymore though. He doesn't have that "need" to fight. He just likes to make sure everyone knows that he is the boss!

They are less agressive. There are certain traits that are just part of the animal, but getting them neutered is a start and you should alter your cat anyway, just to prevent unwanted litters if he should accidently get out.

It will surely help..though it may take a month for all the hormones to disappear.

i think so... but not sure. our tomcat was neutured and he seems very mellow now, but every now and again he attacks our dog! :D good luck, hope i helped!