This package is ideal for reef aquariums up to 50 gallons. It contains a carefully selected mix of herbivores. By utilizing these cleaning organisms, and good overall husbandry practices, aquariusts will minimize their algae cleaning responsibilities. This Cleaner Package has 10 Scarlet Hermit Crabs, 40 Astraea Snails, 5 Mexican Turbo Snails, 5 Trochus Snails (may sub Nerite depending on availability), 2 Lettuce Nudibranchs, and 2 Emerald Crabs. For larger aquariums just order multiple quantities of this package accordingly.