Flagtail Prochilodus are large herbivorous fish native to the Amazon Basin in Colombia and Brazil. Though they are relatively unaggressive, they grow to about 10 inches in the aquarium, and may become territorial. These fish should not be housed in tanks smaller than 75 gallons. As the primary diet of the Prochilodus is vegetative matter, they should be supplied with spirulina or veggie tabs as well as lettuce or other vegetables to satisfy their large appetites. The tank should have plenty of room for free swimming, but also plenty of wood or rock. Plastic plants may also be supplied, as live plants will be devoured.