Addressing one of the most common questions: how did Donnie know it was her? Also, keeping with the 100 words thing. It's a nice challenge.
"Here's what I want to know," Mike said, hammering away. The aquarium was going to take up most of the second storage room, which was right off the main room, for easy access. Don grunted, absorbed in his plans.
"How did you find her?"
Don hmm'd for a moment, thinking, and then looked up at his brother.
"Lucky for us the pet shop we came from has very good records. She was one of their best breeders."
"Whoa, so, like… how many brothers and sisters do we have?"
Don laughed at Mikey's expression.
"Hundreds at least."
Mike's silence was awed.
"Did you pay for her?"
Don threw down his hammer.
"Leo, are you implying that I stole my own mother?"
Mike burst out laughing, but quickly stifled it. Leo's expression hadn't changed.
"Well?"
Don sighed.
"She cost a pretty penny, I'll have you know. She was their prize breeder, so they wouldn't let her go for less than $300."
Leo coughed, eyes going wide. Mike laughed again.
"Now don't you wish Don had stolen her?"
His brothers rounded on him.
"No!"
"Mikey, she's our mother. And she's ours, fair and square, all nice and legal."
Mike drew back, muttering.
"Sheesh."