I have 3 of them myself, they are in a well planted 30 gallon with 1 blue gourami, 1 moonlight gourami, 1 pearl, 1 SAE and 4 thick lipped gouramis, and 2 rainbow fish. I was nervous about them being with so many big fish at first but they quickly settled in and no one has messed with them, ever. They actually pick on the thick lips sometimes..lol I wouldn't suggest them for bettas though, I had a betta in a floating molly hatchery and the sparklings were obsessed with harrassing it constantly. Maybe females could work but I doubt it.
~Danielle