The panda has been scouring for arowana floating fish pellets for weeks now in pet shops everywhere, but it is always out of stock. The arowana gets hungry too, you know. The only thing the panda can do now is to feed his "other" small pet sword-tail fishes. In other words, the panda is feeding his small pet to his bigger pet. It is not a "nice" feeling.
Imagine feeding your small dog to your big dog!
How much more time should the panda wait until that fish food ceases to be be out of stock? Poor fish, you gonna have to be put on a forced diet.