| hi kusuma,
the recipe to create a shiromuji out of kohaku or bekko out of sanke is to put the fish under extreme stress i.e water with high amonia level + high temperature + small over crowded tank for a week or two. if the genetic is weak, the transformation will happen in less than a week time. I have tried it before and it works for some fish (the genetically weak one) especially the small sized fish, but it does not work for other fish (I guess the genetically strong one). This setup can even make a shiro lose its sumi, again the genetically weak one I guess.
I understand this batch of Ogata just arrived to some dealer's place in Jakarta less than two week time? which means they should still be in a high stress condition due to extreme change of climate and water parameter as well. The next few days, you bought them and placed them in your FG tank which has another different set of water parameters, another stress trigger. And they are small size tosai. This could explain the fading color.
What a discouraging experience with imported fish, especially since you have paid a premium price if compared to local bred fish.
anyway, you may want to put them in a quarantine tank/aquarium and try to keep the tank in a shady cool place with lots of oxygen. do not feed in the mean time and change 80% of the water everyday.
good luck. |