I just have to jump in here too! I have 6 different breeds of cories in multiple tanks. If the population drops below 6-8 of the same species, they hide. Otherwise they are out all the time. Pygmaes swim in mid water a lot and are soooo cute and tiny that you could do twice as many as most other breeds. They all zoom to the top, I always thought it was to grab some air. The only ones who ever splashed were the Emerald corys. I also have kuhlis in most of my tanks. I love them too. They are out all day, swimming up and down the glass, foraging amongst the plants and are super charming. There is a group of them in my 55 g who have claimed the left front corner and entertain themselves all day, up and down and around the wood. It just comes down to which ones you like better. I have never had a Kuhli jump out either. They have never broke the surface.