The first trailer for “Finding Dory” let us see Dory, Nemo, and Marlin again but didn't show us much in the way of new characters. Entertainment Weekly managed to get a look at two of them: a beluga whale named Bailey, voiced by Ty Burrell, and a whale shark named Destiny, voiced by Kaitlin Olson.
– Entertainment Weekly (@EW) December 30, 2015
According to the EW article, Bailey and Destiny will help Dory find her family, but they have problems of their own (as does basically every form of sea life in this franchise): Bailey “isn't great at his own sonar capability” and Destiny “has trouble swimming straight.” That's probably why Dory finds them in a rehabilitation center at a marine life facility.
Also, Bailey apparently makes fun of Destiny by calling her a whale when she is actually a shark, which he should really know since he, a mammal, has a horizontal tail and Destiny's is vertical. I mean, it's right there in the picture. Couldn't be any clearer!
“Finding Dory” is set to be released on June 17, 2016.