This creature was a mistake from the natures side. It was a combination between the arms of man, and the body of fish.
Unfortunatly, nature mixed up their breathing system, and ended up adding neither lungs nor gills. The result was a creature that couldn't breath.
But the breathing problem wasn't really a problem untill after some years, you see, this fishboy didn't use too much power, and therefore almost didn't need any oxygen. Two minutes three seconds and thirty milliseconds, before it died, the fishboy looked like this: