mickey mouse fish behavior

Question
I KNOW THAT EVERYTHING SAIS THAT MICKEY MOUSE FISH ARE PEACFUL BUT MINE SEEMS TO BE PICKING ON THE BIGGEST FISH IN THE TANK.I HAVE 2 MICKEY MOUSE, 3 GOLDFISH, AND 1 FANCYTALE GOLDFISH.THE BLUE MICKEY MOUSE SEEMS TO BE PICKING ON THE FANCYTAIL GOLDFISH AND NOW THE GOLDFISH IS SWIMMING WIERD AND TURNING WHITE.IS THERE ANYTHING I CAN DO BESIDES SEPERATING THEM OR DO YOU THIN K MAYBE THE MICKEY MOUSE IS PREGEANT AND ACTING THAT WAY? I DONT KNOW WHAT TO DO AND REALY DONT WANT TO SEPERATE THEM.THANK YOU FOR YOUR TIME.

Answer
Hi Betty,

You have a big problem in your tank. It's not the aggressiveness, but the fact that Goldfish and Tropical fish (platy) are being kept together. Goldfish are coldwater fish, and require temperatures of 70F and below, while tropical fish need temperatures of 75F and above. You MUST return the Platys immediately, or they will die soon. If you don't want to return them, you will have to get a separate tank for the Platy fish, with a heater. No temperature is suitable for both Goldfish and Platy fish. Tropical fish need heaters, and Goldfish do not.

In the future, if you notice aggressiveness between tropical fish, you can add some plants, which will provide hiding spaces and reduce aggressiveness.

In the future, don't keep Goldfish and Tropical fish together.

Good Luck, and Happy Fishkeeping!