Wrong forum. They are a tetra. Exos are super cool and beautiful fish in schools of 8 or more. They are like danios in the fact that they NEVER stop moving. Sometimes they can be expensive. I have seen them close to 15bux a pop, but I have also found them cheaper, even as low as $3 a piece. If you have the extra tank (good size as they are very active) and find a good deal I would highly suggest grabbing them up!
They will eat anything including feeder guppies. Selecting tank mates for these guy can be tricky. IME bottom dwellers, especially armored ones like plecos and doradids will not get messed with. If a fish is too small it can get eaten entirely by an exo but a large fish can also have exos pick the scales off one by one.
All in all very neat fish, but rather difficult to keep because the tank space needed for such a small fish as well as the difficulty in choosing proper tank mates.