Cha-san is used to grazing. Eating a little bit here and there when he feels like it.
If he is not hungry, he does not mind Mochi eating his food.
However, when Cha-san is up and wanting to graze, he will take Mochi’s food even when Mochi is there trying to eat.
So mama-san moved Mochi’s feeder, which opens with timer, up the stairs thinking Cha-san could not climb stairs. Now he does.
One early morning, mama-san heard hissing. Seems Cha-san pushed Mochi away from her feeder. moma-san got up and saw Mochi coming and looking at her.
mama-san came to let Cha-san be away from Mochi’s feeder, but the food was pretty much gone.
When mama-san placed food for Mochi, Cha-san tried to take it again, this time Mochi stood her ground and they had a short neko-punch battle. (Paw fighting but no claws or screams ). mama-san picked up Cha-san and took him back to his room. Cha-san did not like that and make a loud objection.
Now, He has a auto-feeder that only he can open and eat from.
Hopefully that will help, but time will tell.