Coldwater fish

Question
Is it alright to keep Goldfish in a tank with no heater, filter etc. But instead clean the tank out regularly?

Also, what sort of fish could go in a coldwater tank with them?

Thanks in advance.

Answer
You will never need a heater for goldfish. They like their water at around 18 degrees C. No heater is needed. Filters will make your life much, much easier. You won't have to clean it our very often and it will make them heaps more happy. They will also need aeration so you will need a pump, this can also connect to a filter so it is probably getting a filter as well.

There are lots of other cold water fish that can go with goldfish.

White clouds, Danios, some Catfish and Loaches, water Snails. Just any fish that don't need tropical temperature waters and are not too small for the Goldfish to eat them.