Goldfish are Carnivorous
Goldfish are carnivorous. They make look pretty empty headed, bubble brained and appear to be no threat at all. But, they do eat more than just plants. If you've assumed your local goldfish was harmless, you need to rethink things.
Imagine goldfish trained to be aggressive, bloodthirsty even. Someone who is really into weird, macabre stuff has put goldfish in a pond and trained them to eat meat. They begin by throwing in bigger bugs, then the odd chipmunk and then a squirrel. In a few months, just before the end of Autumn when Winter is closing in, the goldfish are tearing chunks of flesh off a side of beef. It's almost like they have teeth! Kind of sick and twisted.
The goldfish overwinter in their pond as goldfish will. (All of ours survived this year!) But the twisted owner of the goldfish and their pond accidentally falls in when he works at chipping ice away from the top layer. He is almost instantly eaten by the goldfish who have just been waiting for a good meal to end their Winter-long fasting.
The house where the pond is eventually goes up for sale. No one really knows what happened to the owner (or several dogs and cats in the area) but he is assumed to have abandoned the place. So the city claims it and sells it cause it's a mess and they'd rather not have to bother with it.
The new owner of the property loves fish. He soon realizes all those bones in the bottom of the pond are not just a coincidence, however. Still, he leaves up the signs for "Fluffy" just in case she comes back.
He decides to market the man-eating goldfish. People come from all over to see him drop chunks of meat into the pond and have the goldfish swarm and devour it all. He gets a nice stash of money and builds a nicer house. He even spends a bit on a monument to poor Fluffy who never did come home.
But, goldfish don't last forever. After ten years there are just three of them left. They have grown to a huge size with appetites to match. He hasn't had luck saving the fertilized eggs any time they have spawned, they just eat them too quickly. The remaining goldfish can't be expected to last much longer. Still, the show must go on! So he sets up a new pond and begins training a new batch of goldfish to be man eaters. Of course, it takes time. Evolution can't be rushed.
However, what he doesn't realize... the original man eating goldfish feel they are not getting enough to eat, now that he is so busy training new goldfish. So they evolve a bit, just because they can. One night they evolved stronger fins, they push/ pull themselves out of the pond and push/ pull themselves along the grass and push/ pull themselves into his house. They snack on "Rover" and get a few bites of "Hunter" before the dog realizes he can run pretty well with just two and a half legs if he really has to.
For all their evolution with the fin legs, the goldfish still can't breathe out of water for long. They can smell water in the house so they head for it. In the morning, when the home owner walks into the bathroom he finds them in the toilet bowl. After a little scream of surprise and another gasp of fear and a sigh of resignation, he gives them the big flush. The goldfish circle down the drain, on a roller coaster ride to the sewer system. They live there just fine. They breed cause down there the eggs have lots of debris to float around in, undiscovered by the parent fish.
So now you know... they're out there.
How would you change the goldfish story? Would you rewrite it entirely with your own ideas or just edit it to add details or humour or better spelling?