For a long time ago, the arowana or siluk was not hunted by the villagers that lived in numerous villages that dotted the numerous rivers and lakes in Kalimantan, Indonesia.
This changed when people believed that arowanas would bring good luck to their owners and soon this fish became 1 of the most expensive aquarium fish as demand outstripped supply. In their natural habitat, arowana population plummeted because of poaching for the aquarium trade and is now being classified under the red list of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
When the aquarium trade on arowanas first started, it was thought that arowanas were harvested from Kalimantan will always turn red or orange when the arowanas mature. However we now know that this is not true although the young arowanas had red fins and look very alike. The arowanas from Western Kalimantan along the Kapuas River region will turn orange or red when mature while those from Southern Kalimantan along the Bajarmasin region will remain silvery with yellow tails.
Naturally, differences in the colour of the arowanas also meant a difference in their prices. However, it would be difficult to identify a young red arowana from a young yellow tail as their young had similar features and red fins. The redness in the yellow tail arowana's fins would disappear only as the arowana matures. To differentiate between the 2, red arowanas from Kapuas region were called grade 1 red while those from Banjarmasin were called grade 2 red or Banjar red or 1.5 red.