I have a few questions about pet pvp battles. 1: What level does your pet have to be to participate? 2: How do you enter a normal pet pvp match (not practice)?
You pet can participate at any level but I don't think a hatchling would do very well. Once you do 5 practice matches on your pirate, then you can do the real thing. As your matches increase you will be able to use more pets at once.