this how to know if cats play or fighting

Examine their hair.

Cats that are engaged in a real fight will have their hair standing on end. They do this to make themselves look bigger. Therefore, if you see puffed up hair on your cats’ tail, body or both, then they are more likely to be fighting than playing with each other. --------
---vetstreet.com/our-pet-experts/how-can-i-tell-if-my-cats-are-just-playing-or-actually-fighting