X-ray Tetra are small schooling fish that live in the Amazonian coastal waters of South America, more specifically near Brazil, Venezuela, Guiana and Guyana. They are able to live in fresh water and can adapt to brackish water. They are found in the section of water between the bottom and middle.
Another interesting thing about the X-ray Tetra is its bony internal structure. It is a Weberian apparatus which Dictionary.com defines as
"(in certain fishes) a chain of small bones and ligaments connecting the inner ear with the air bladder."It is used to pick up sound waves which accounts for their acute sense of hearing. X-ray tetra are pretty peaceful, getting along well with other species that share their space.
Their diet consists of small crustaceans, worms and insects. The biggest threat to the X-ray Tetra is water pollution.
You can find more information about them at Wikipedia, One Kind and a-z animals.
This is Day 24 of the A to Z Blogging Challenge.