I bought 2 yoyos roughly 2 years ago and unfortunately one decided to kill itself by jumping out of the tank while i was at work. The other one over time made friends and became an honorary Congo Tetra and still kind of is.
He spends most of his time either hiding under his piece of wood or swimming with them, even in tight formation
Roughly 3 weeks ago i introduced 4 new Yoyos to the tank, they are roughly a quarter of the size of the one i have already, was worried he might get territorial, or even just reject them completely and id have 4 deceased Yoyos and back to just one!
I couldnt be more pleased than when the lights are on or im home from work, to see 5 Yoyos playing around and interacting so nicely together. It appears that they even share the same home as the older one! Theyve taken to digging vertically together and swim occaisionally in a tight formation themselves.
Oh and the space of 3 weeks the new ones have pretty much doubled in size, they must be happy!