Hello here! I am a total newbie so I need your expert advice here. What the best fish to have for a new one? I heard that Guppies are suitable for this. Also how many gallob tank do I need? For example, I'd choose a 10-gallon tank - how much fish can live there? It is necessary to have a tank heater like this one? It sounds weird for me because in the nature there are no predictable water temperature. Sorry for these silly questions Thank you in advance!