For larger plecos ([SIZE=-1]Hypostomus[/SIZE] spp) Raw or cooked prawns whole will be appreciated or even a small slice of fish fillet occasionally. In the wild, fish would be constantly foraging for food so they are always looking and eating by instinct. In aquariums its quite different since they dont need to expend much energy searching and food is very nutritious and plentiful. For larger fish including plecos I would only feed twice a week unless I am trying to actively grow them. However, I am told that fish which grow rapidly have shorter lifespans.