There's really no way to stop adding to the collection... You could try my solution (be warned: its only a temporary one)... RUN OUT OF SPACE!

Honestly, I started with 1 Dendrobates leucomelas almost a year ago... 11 months later, I have added 43 more frogs to the collection

I am at a point now where my grow-out tanks for froglets are on the floor in front of my rack... I am waiting for 4 more frogs to show up next month from Understory Enterprises and have about 20 tadpoles in the water...

I only have dart frogs at the moment... Once I have an entire room dedicated to frogs, I'm planning on getting a bunch of different types of tree frogs and an African bullfrog...

-Christian