Releasing now can give you bonus gold!
Daily Bonuses have arrived!
Daily Bonuses can be seen in the sidebar on the home page, and change daily. Basically, if you release a pet of the species or a pet that contains the marking of the current day, you will receive extra gold when you release that pet.
By keeping track of the Daily Bonus, you can earn quite a bit of extra gold, just be sure to breed a lot of different species and markings :)