i dont know anything about snowflakes being nocternal and not coming out during the day. they do get alot more active at night but mine are out all day long always hangin around beggin for food. i would start with one of them before you spend the money on a zebra being a beginner. i have lost a couple due to carpet swimming, they will find any hole in the lid if they decide they want to see if the water is wetter on the other side of the glass. plus they dont get as large as the zebra. you could do a few other fish but space them out try to start with the least aggro fish first and add the most aggro last after the peaceful fish have already staked there claim.