The blue tang is called many names. In latin, it's Paracanthurus hepatus but usually people call them Hippo tangs, palette surgeonfish, or regal tang. And of course, from the movie Finding Nemo the blue tang is called Dory. While I've kept them in the past in previous tanks, this fish was beckoning me to purchase it before Finding Dory released in theaters. It's been growing slowly. This image was taken October 2017. At some point, I'll have to move it to a larger aquarium.
This comical looking fish is a fun addition to any tank, and even I couldn't resist its charms when it posed for my lens. Lawnmower Blennies do eat algae, but I've watched this fish swim up and try to take a chomp of Spock, literally trying to latch onto her body as if there was algae to consume. Of course, Spock was furious, turned hard and fast sending the blenny into a hasty retreat. She'd pace the tank a couple of times, basically muttering to herself "As if I was a moss-covered wall... tsk!"