pirarucu is the local name of the arapaima in the amazon. arapaima if i'm not mistaken is the scientific name. i've read somewhere here that there are actually 3 or 4 sub species of the arapaima.
What do you mean the pictures don't go along with it? A pic with the title of arapaima should look just like a picture with the title of piraracu lol...
arapaima gigas is scientific name and piracru is the local name and they are the same,when younger there head is normal when bigger theres like a hump shape due to fat
Hao has it right. The head/body shape and color pattern changes with age. These should start coming in soon but you need to be sure you understand what you're getting before you aquire one of these, as they are a true commitment. This species gets huge! It is one of the largest freshwater fish in the world.
Mark