What to feed Pleco fish? Do Plecos need to be fed?

So you got an algea eater, it can be any type of pleco: common pleco, plecostomus, bristlenose pleco, ....and they doing a great job getting rid of your brown algae or green algae. So, do you think you need to feed them....? פלקו, פלקוסטמוס, אנציסטרוס