There are many backwater rivers that make up the Amazon River basin. Due to the lush rainforest canopy, and its regular shedding leaves and fruits, the waters are high in organic and nutrient compounds. Fallen trees also contribute to a narrow swimming environment conducive to thin, laterally compressed fish species. The water's color will vary from clear to reddish-brown, and even black depending upon the stream’s location and nutrient levels. Reddish-brown to dark-brown gravel is recommended to simulate the natural substrate. Plenty of driftwood and plants are essential to recreate this niche.