red scooterblennies dont eat algae, they are picking and looking for Pods, pods are those little white things that look like lice, probably all gone by now. scooters and mandarin gobies are known for wiping out these populations in a matter of weeks. Soon, they will starve to death. Luckly, there are alternatives. You should try feeding it brine shrimp or mysis shrimp. Try turning off all powerheads and let it sink to the bottom and let the scooter eat it. If you have problems with something stealing it, shrimps and crabs. Try getting a Skewer(wooden sticks for bbq) and poke some mysis on it. Feed it that way or you can use your hand and block the way of the shrimp. They do not eat flakes. Mandarins rarely eat brine/mysis, sometimes they do. One way to see if its starving is to see its stomach sink in(under hte scooter).Hope this helps