The eggs told them the fish was an adult female, yet it was less than half an inch long. The transparent catfish is among the smallest fish ever found, and it has an unusual way of protecting itself from the abrasive effects of the swirling sand in its habitat at the bottom of the river. Lundberg says, meaning they don't have scales like most fish. Other Amazon oddities include two species of electric fish that thrive on a most unusual diet. They eat the tails off other electric fish, but that doesn't kill their prey.
Victims simply grow another tail and move swimmingly along until they encounter another predator.
More Than 2,000 Species Lundberg's team, which includes scientists from Brazil, has collected more than 125,000 specimens, representing 240 species. That's a lot, but it's a drop in the bucket compared to the biological richness of the Amazon basin. Lundberg's team has explored about 2,500 miles of the Amazon, and most of it turned out to be relatively pristine. Some logging operations have increased silting in the river, and some industrial areas have released toxic chemicals into the system, but generally he found the river brimming with life. The proposed hydroelectric facilities could make it impossible for many species to travel the great distances they need to survive.