Do I need a filter in a QT tank?
I have a 20 gallon community and I want to add 3-4 more tetras. I have a spare 10 gallon and 50 watt heater, but I don't have a filter. I can buy one but I would prefer not to right now, I don't really have extra money. So would 3 glowlight tetras be okay in an unfiltered 10 gallon? How often would I need to change the water? Thanks.