I am planning on getting a 20-gallon tank but I'm not sure what to stock it with... So far, the biggest tank I've had is a 6 gallon. What kind of equipment/test kits should I get for the 20-gallon tank? Is it fine to just buy a Petsmart 20 gallon tank that includes supplies, or do I need to look into the supplies more? When it comes to the fish, I am looking for long-living strong fish that won't reproduce but will make my tank look more interesting. I am also planning on keeping mystery snails- how many can I keep? Is it okay to keep cory catfish in a 20-gallon tank? What about electric blue lobster? Can I transfer some of the fish from my other tanks into this new tank or would that expose them to disease? Should I quarantine the fish that I buy before putting them into the tank? Would it be okay to have a betta fish in there with the other fish I am planning on buying or will it nip at them? Sorry, I am very new to this and just want to make sure that I am getting the best possible fish tank and supplies.