Bubble Guppies/Headscratchers

Okay. So, Oona's fish tail reaches all the way to her shoulders, unlike Molly and Deema. Does that mean, when she grows up, she won't have human mammary glands? That's Fridge Horror right there.
 * Maybe the tail covers all of her body.
 * I've been thinking. What if, instead of the usual bikini top, Oona is wearing some kind of dress that covers her entire tail. The dress just happens to have the exact same color pattern as her tail, so it's hard to tell she's wearing one.
 * So, in "Call a Clambulance!" how exactly did Deema acquire a pair of human legs and a Triceratops for the x-ray?
 * Why do they need a fire department underwater?
 * Well, people do still get stuck in trees.
 * Why are there underwater penguins in the zoo?
 * Because they are Mer-penguins.
 * So what do they eat?