It's not like Bloo and Frankie are enimy's. I'm sure they get along. You see that they do smoetimes. Frankie even say's that Bloo is "an awesome friend" in House of Bloo's. Ofcourse, that's before she gets to know him better.
But an episode where the two have to work together, for whatever reason, and actually getting along long enough to finish the job in the end, would be a nice episode.
