There are 2 types of pets in the game:

Growth pets and
Ability pets
RESTRICTIONS: You must be at least level 5 in order to be able to summon any pet. You may have a growth pet simultaneously summoned with an ability pet, but you can't summon simultaneously more than one ability or more than one growth pets.

WHERE TO GET THEM: Some pets can be bought in the game by paying with gold and some can be bought only through Item Mall (F10) by paying with silks. Pets that are bought through Item Mall can't be sold or transfered to another player. But if you have more than one characters in a server you can transfer your pet from one character to another by leaving the pet in your storage.

PET'S NAME: Once a pet's name is set, you can't change it later so be careful not to make any spelling errors when you give your pet a name. If you have a pet that can be sold (as Grey Wolf), think twice before giving it a name. If there is a probablity that you may want to sell it later, it's recommended not to give to your pet any name. Named pets worth really less than no named ones, because when someone wants to buy a pet he will prefer a no named one in order to be able to chose a name for himhttp://www.silkroad-online.gr/index.php?display=pets&lang=en