Originally Posted by CDGQY
Could I/should I put a tiny baby goldfish in my guppy tank? I came upon some eggs when cleaning my goldfish tank. In retrospect, I should have returned them to the tank and let nature take its course. Now I have one survivor about a month old and still remarkably small. I cannot put this little fighter back in the goldfish tank where heíd be a snack in a heartbeat. I feel sorry for him being alone in his tank. I doubt I could find a similar sized companion. My guppy tank currently has fry about his size Yes, I am a sentimental old fool. That aside, what might be best for the little goldfish?
You can put Goldfish in with Guppies. But, keep the tank water cool. 74 degrees is the top end for Goldfish. Warmer water isn't recommended because this will increase the metabolism of the fish and they'll poop more. Besides, cooler water has a higher oxygen content and that's better for the fish. Guppies are fine in cooler water. You wouldn't even need to heat the tank. As long as the Goldfish and Guppies grow up together, there's little chance of the Guppies becoming lunch. Feed the fish regularly. Adult fish that are well fed, show little interest in fry. Heavily plant the surface for hiding places for the younger Guppies and females and as a fiber supplement for the Goldfish.
Goldfish need a bit larger tank. 15 to 20 gallons for the first fish and 5 gallons more for each additional fish. Keep the water clean with lots of large, regular water changes and you'll have no problems.