Actually, it depends on what a crocodile is and what a piranha is. If you throw an underage crocodile into the pool, the crocodile can swim just after a foul, but its ability to protect itself is very poor. The Nile crocodile ranked second in the world, its cub is only about 30 cm long. If such a small crocodile enters the pool, it may become a free lunch for piranhas. Of course, if adult crocodiles are lost, piranhas will also be in danger, because crocodile teeth are much sharper than them, and even cheetahs will die under the unparalleled bite force of crocodiles. In addition, there are some crocodiles living in the Amazon River. Their territory overlaps with piranhas, but local people rarely see piranhas killing crocodiles. Why can't piranhas kill crocodiles?
This is related to the predation mode of piranha. Because there are many fish in Amazon and the water quality is turbid, piranhas can't see their prey clearly by their eyes, and generally rely on their sense of smell and hearing. When they smell blood or hear a loud noise, piranhas will flock to surround the prey that falls into the water and then eat it in one bite. On the other hand, crocodiles, we also know how to hide in the water for a long time. In the absence of prey, they rarely move around except breathing, which can't attract the attention of piranhas.
Crocodiles themselves are very powerful. As an ancient animal at the same time as dinosaurs, their life-saving activities attracted many things, among which hard and thick skin may not be penetrated by bullets, not to mention the small row of teeth of piranhas. Although in our eyes, piranhas are fierce and have sharp teeth, which can bite off people's fingers and toes and pierce people's skin, in the eyes of crocodiles, piranhas are just a bit hard prey. In the Amazon river, some crocodiles also prey on piranhas. But piranhas. After all, it is fierce. If a small crocodile provokes them, their legs and tails will be broken and their weight will be in jeopardy. But the crocodile is not stupid, there is danger in the water, and he can run to the shore, so the piranha can do nothing.