Hello! I currently have a single male betta in a 2.5 gallon tank with a heater and filter. He has been doing well since I got him at the beginning of this year. At this point, I would love to move him into a larger home. My boyfriend and I have been discussing getting either a 5 or 10 gallon tank for him. This little guy is pretty much our first fish-- we had one other male betta before him for a few months, but we had a thermometer malfunctioning disaster and he passed away despite our best efforts So far so good with our new boy! I'm hoping to get some advice on what size tank would be best to upgrade to, and how to go about preparing the new tank before moving him. I know getting it cycled is important, but I don't know a lot about how to do it (I've heard you can use parts of the old filter, or some rocks from the old tank to get it started?). We'd also love to get a few tank mates, if possible. Are there any fish or invertebrates that can co-exist peacefully with a male betta if the tank is large enough? Thanks!