For most people, the name sparks horror-movie __1__ of vicious ( 凶恶的 ) schools of fish that can reduce a human to a skeleton ( 骸骨 ) in minutes. But do they really ___2___ this fearsome _____3_____? Piranhas are freshwater fish that are found in rivers and floodplains of South America. The most ____4____ species is the red-bellied piranha, but there are nearly forty other different species of piranha. They aren’t very large, but do have a mouth full of __5__ teeth and a strong jaw. So it may surprise you to learn that piranhas are not the bloodthirsty killers described in films. For most piranhas, their __6__ is mostly made of insects and other fish, but also plants. During the rainy season when food is ___7___, piranhas eat more plants and insects. But in the dry season when ponds and rivers dry up and food becomes more __8__, piranha turn to meat-eating, usually in the form of other fish. Piranhas ___9___ bite humans when very hungry or threatened, but serious attacks are ___10___ rare. Another common __11__ is that piranha form large schools for hunting, allowing them to attack larger prey ( 猎物 ) than a single fish could. However, researchers found that piranha most likely group together as a defense against other animals. So while piranha may not win your hearts with good looks, they are ___12___ more victim than vicious.