wierd_world on Instagram: "Piranhas are found throughout the lowland freshwater river systems of South America, including the Amazon Basin, the Orinoco, the Paraguay–Paraná, and the São Francisco River systems, covering countries like Brazil, Argentina, Colombia, Venezuela, and more.​Appearance: They are typically small-to-medium-sized fish (usually 5–10 inches/12–25 cm, but some species can grow larger) with deep, laterally compressed bodies. Their colors vary, but many are silvery-gray or gold