n tropical streambeds, aquatic plants are found growing in a special clay called Laterite.  FIRST LAYER is an all natural Laterite in a granular form, which is ideal for aquarium use.  The pure Laterite in FIRST LAYER provides the perfect planting medium for a natural aquarium.   Mixing all natural Laterite into the gravel bed creates an excellent planting medium for rooted aquatic plants.  Safe for use with tropical fish. 

API First Layer Pure Laterite 20oz