Khun Jerachai,
There are at least 5 species of Peacock bass. How can you be sure that the one you've shown is Cichla monoculus.
The five species that I mentioned are Cichla temensis, Cichla ocellaris, Cichla intermedia, Cichla orinocensis and Cichla monoculus. Anyhow,when people mention peacock bass, you have to assume that there are atleast five possible species. Unless this is your own fish and you have done all the scales counts and measure every possible morphometric measurements, you can not say for sure what species they are. I just don't want people to mistake this unintentional statement.