I have and 8 year old male Rotti/Chow  that is sweet as pie never been aggressive. I also have a 2 1/2 year old Yorke Mix both males not neuter. The younger male has starter fighting with my older dog should I go fix the younger one.

If castration is done, it should be done to the more submissive one.   If the aggressor looks to start and fight but gets no reaction, that 'should' shut all this down.   BUT just know, castration will only prevent unwanted litters.   Most of the rest is down to prevention/correcting unwanted behaviour. 

Fact is we had a situation where, having kept one of an all-male litter, by the time he was around 18 months he started challenging his uncle (who had been used at stud, but the young lad hadn't) and they were having increasingly nasty fights.   I tried everything to get him - it wasn't his uncle who started this but clearly he wasn't going to put up with the young pretender! - to stop but eventually I had to find him a home.  He went off happily and peace returned to our small pack.

It's totally up to you whether to castrate or not, but castration may not solve what's going on.

It might help, but I doubt it.  Have both dogs had a thorough medical check to make sure there's nothing underlying?

If that's all clear you need to be managing the situation so that fights do not occur - close watch when they are together, not leaving them together unattended, removing all potential triggers such as chews, toys, feeding them completely separately and possibly removing you if your proximity is a trigger.  On top of that, you need to be making sure that any interactions are good and rewarding them and anything else good too (I usually use food but if treats are a trigger, go with whatever works without making things worse) - so if they so much as look at each other calmly, reward it.  Stay calm yourself, of course, and be careful about how you correct them if anything does happen - calm removal and timeouts is fine, telling off/physical corrections is not because it will add tension to an already tense situation.