I looked them up, and they, (the fish Gods) recommend 50 gallons for the Snowflake (although I have kept a medium sized Snowflake in a 29 gallon with a Red Reef Lobster and they lived happily for years) and 125 gallons for the Zebra. I think that size makes all the difference (despite what you may have been told about magic and such) if they are small to medium, they should be fine in a 70 - 90, but when they get larger, you will have to up size.