The water was very well oxygenated, but that peacock bass died unreasonably(maybe the shrimp was kept frozen too long). But there is also a good news, that is on the day of the its death, the other peacock has accepted pellets, it eats everything drops from my hand now. But once the pellet has landed and floating on the water for more than 1.5 seconds, it will ignore it and wait for new pellets being dropped into its mouth.