Filling your pens with tons of slimes can make you a lot of money, but they can escape easily. This guide on How To Stop Slimes Escaping In Slime Rancher 2 explains how you can upgrade the pens so that the Slimes are unable to escape as each slime can escape in different ways.
This is very likely a mechanic from the first game but if, like me, you didn’t play the first game, you may miss this. Once you have placed a pen and filled it with slimes you can interact with the building totem that lets you build items at the various plots around the Conservatory. Using this totem then allows you to place upgrades on the pens.
How To Stop Slimes Escaping In Slime Rancher 2
For example, the Red Slimes can jump quite high, so you want to buy the extra high fences to stop them from escaping. Likewise, some of the other slimes create towers from each other and then use that to climb over the top, for these ones you want to put on the roof.
There are various upgrades to all of the buildings in the game, so make sure you explore these options whenever you construct something new.
in Slime Rancher 2 Guides