I currently have a flametail and lawmower blennies in the same tank, had 3 blennies at one point, but gave the 3rd blennie away to a friend, they all co-existed just fine in the tank together. They are like tangs, sometimes they get along, sometimes you get fighting. I am going to try putting a midas in my tank soon to see if I have the same luck I did before. Just need to catch the darn yellow tang to offset the bioload from the 3-4 new small fish I want to add. Just be sure to have a healthy pod population for the scooter and you should be fine.