Nano V SOFT-FREEZE is a range of frozen foods that are kept in the freezer but they never freeze hard. This means you take the food from the freezer and it is READY TO USE! SUPER CONVENIENCE in a concentrated, high quality food. NSF foods are excellent for the small NANO aquariums because you feed a small amount of food – only as much as necessary. Therefore, you don’t have to deal with a cube of food in cases where even a single cube is still too much. Because NSF foods are kept in the freezer, they will never spoil. We do not have to add preservatives or acids to keep the product FRESH.