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.