You can choose any pet to combine to summon a vice pet (the chosen one WILL NOT disappear)
To enhance vice pet, you can feed them fishes just like your primary pet.
To upgrade vice pet, you have to feed them another vice pet that you don’t need.
You can transfer the status of the second pet too (like inherit, but the status will move completely to the transferred pet).
There are 3 choices to transfer the status : 60%, 80%, dan 100%