hey there and welcome.
I had the same problem when i introduced a new tiger into the existing oscars tank.
The tiger behaved like it never had gotten any food at all.
Splashing and jumping and grabbing all the food in sight, leaving hardly any for the much bigger red o.
Feeding in 2 different spots may help ,as well as mixing sinking with floating pellets.
I threw in a handful of of those to begin with, and the pellets will float around and will spread, so both fish will get their share.
Or mixing some mealworms with pellets may help.
My tiger calmed down after a month or so, and finally seems to understand that he doesn't have to fight to get the most food.
Now both of them come up to the surface with their mouths open, so i can toss the pellets in...