Kale is probably the best food for bushynose plecos. All you have to do is freeze it. When you want to feed it yo just pull out a leaf cut it into the size pieces that you want and anchor it with a clip or a fork. It usually gets devoured the second day when it starts to break down. It is about the richest food there is with high protein and all 9 amino acids.
Here is what it contains in vitamins alone.