The colors can varry greatly based on setup or mood. Some species more then others.
You will get best coloration in a dark tank . This has nothing to do with adapting to blend in they simply are stressed in bright environments causing washed out colors .
Many species also have diffrent coloration when breeding vs the rest of the year , and in the case of Emperour snakeheads (and many others) they also have a very large natural range and color/pattern varries greatly depending on collection point .
The differences your seeing in pics of emperours are most likly the result if them being from diffrent localities.
