Defo bored with the food, welcome to the fussy world of large Asians. Just wait till you have to play a guessing game with regards to what it wants to eat today!! The more food types I've introduced the fussier my RTG has become.
My fish went 4 weeks without eating anything because "i'm the boss"!
If i don't feed my RTG for 2 day then feed it shrimp it will take one piece, the rest it will play with. After that I'm lucky if it eats one piece.
Besides it healthier for his fish to have a varied diet. The same everyday is not good for them.