Dont do it. If you are having algae issues there are other ways of solving the problem. My best friend has lost more flowerhorns to issues that were cause by plecos. Three biggest issues. 1st. They eat a natural filter (algae) and produce waste. 2nd They can latch on to a flowerhorns head and severely stress the fish out/ kill the flowerhorn. 3rd Their spines on their fins are very rigid and sharp. Flowerhorns are naturally inquisitive fish and often bite at the plecos. I have watched the spines of the pleco pierce through the lips of flowerhorns and then infection sets in. Moral of the story: Say no to plecos.