What do you mean by bleached like boiled?
Blanched, placed in boiling water for about 3-4 minutes (depending on the thickness of the cut of the vegetable) then rapidly cooled to prevent cooking it.
I use a half dozen zucchini a week, cut into spears, blanched and then individually frozen on a cookie sheet, then placed in my freezer container. When I want to feed them, I take out about 1/2 dozen spears, pour boiling water over them to defrost them, drain and weight them down by spearing them on a stainless steel shish kebob skewer. The fish tear them up - skin and all - in about 2-3 hours.
For green peas and spinach, I use frozen and just pour a little boiling water over the peas or spinach to defrost, then with the peas, squish them out of the skin before feeding.
Spinach tends to have a real laxative effect, so I do not feed it every day. It is very helpful for a fish that needs some assistance in moving a sluggish system along.
Fruits I feed raw. For oranges, I wash the rind and quarter, removing the triangle ends of rind so the fish can get to the pulp easily. Bananas I just slice length wise, remove the peel and feed halves.
When my goldfish were in an aquarium, I only fed fruit on water change days due to the high sugar content. Now that they are in the pond, I feed fruit a little more frequently, and have not noticed any effect on water quality.
I feed veggies and fruits in the morning. Any remaining food is removed the next morning.