It is to get down to 31 F tonight, the first night below freezing, so I brought my 7 goldfish inside and put them in an aquarium.
They did great all summer, without a filter or pump in the pond, but now that they are indoors, I have a Marineland aquarium, 30 gallons, set up, with a model 200 size filter (really designed for a larger tank than mine-- say, a 50 gallons, which the worker recommended for more aeration since it will have more output since it's really for a 50 gallon, not a 30 gallon) and a biowheel which is supposed to generate healthy bacteria. Aquarium gravel on the bottom.
I bought a gravel vacuum. The worker said a pump isn't necessary unless the electricity goes out.
The worker, who has aquarium fish, says goldfish do not need a light, unlike tropical fish.
I plan to do a 15% water change once a week.
The house is currently unheated, so I shouldn't have to feed them too often. I will move the floating pond thermometer indoors tomorrow to see how warm the water is. Six of the fish were easy to catch in the pond, but the 7th, the sole black one, hid in the black water. I almost didn't find him. He was on the bottom, and I had to remove all the water before I could spot him in the black murk. He looked dead but revived quickly in the aquarium water.
They all gravitated to the 'waterfall' from the filter in the aquarium at first, but are now swimming around throughout the tank. The measurements of the tank are 29" X 14" or so. I read that you multiply that and divide by 30 to find the inches of fish your tank will accommodate. I think it might be a bit too small for my fish. I think I'd better set up a second tank. What do you think? A couple of the fish are small, but 5 are probably about 2.5", minus their tails. I heard you don't count the size of their tails.
At least I have tried to save their lives as my outdoor pond is too shallow for them to safely overwinter (only 18" in depth), and I'm sure no pet store will take them. I've had them since last March.
How often should I do water replacements, given the smaller size of my tank (30 gallons) and number of fish (7) in it? I am going to buy Spring Water for the water replacements, since our tap water has fluoride.
How often should I feed them based on water temperature?
Is it true the pond water won't protect them? Should I bring in some of the mud from the bottom of the pond and place it in the tank?