Frankie is an olive brown fish with light brown fins and light brown lips and wears blue pants and a black belt with a silver belt buckle. He looks similar to Fred, and a younger version of him. But, just like Fred, he said "My leg!" in the episode "Larry's Gym."
When he was driving by the Krusty Krab, the grill fell on his boat then exploded. Like Fred, he yelled my leg, but after said he was okay. The grill then fell again on him and he said that he was slightly less okay.