I got a new 5.5 gallon tank for Dumbledore and gave Jonah Dumbledore's old 3 gallon, both are very happy with their upgrades.
Now that Dumbledore has this big tank all to himself, it's looking a little empty with just one little betta in there. Could I put something else in there? I don't know how aggressive he is with other fish, he's never seen one for as long as I've had him. I don't think 5.5 gallons is big enough for a school of fish like tetras, but maybe something that does well in low numbers or just 1?
Also, how often should I be cleaning it? I've been doing 50% changes once per week with a gravel vac. It isn't cycled, but it does have a filter. I don't know my exact parameters since I haven't been home in almost a week.