David Giblin, age 10, of Glendale, Arizona, for his question:

Where do Piranha fish come from?

These fishes have a terrible reputation for murder and massacre. They deserve every bit of it. Their native home is in South America where they thrive in the slow, muddy streams that feed the Orinoco and great Amazon rivers. There the toothy little monsters gang up and devour any living creature that comes within range. A human swimmer who enters a stream infested with piranhas does not stand a chance. In five minutes, these fierce fishes can strip all the flesh from his bones, bite by toothy bite.

There is a good reason why people should know these gory details. Piranha speci¬mens have been brought for exhibit in large public aquariums where they are safely controlled. However, a few foolhardy folk have gotten hold of piranhas to show off in their home aquariums. This is dangerous. Some of these people had gotten rid of their piranhas by dumping them into a nearby stream. This is mighty dangerous. There is a chance that some of them may survive and multiply, in which case our streams would become disaster areas.