I haven't really counted them in a while, I had 6 originally bought last January. Tonight it occurred to me during feeding that there were only 4 up there eating. Which isn't entirely unusual, there would often be one or two swimming down around the bottom. But I searched all over and I see no signs of the other two, nor no bodies. I suppose if they had died the shrimp and snails would make quick work of them. Not sure what happened, anything I should keep an eye on? Water parameters are good. Everyone seems happy and healthy and eating well, all 12 cardinal tetras are still accounted for, the remaining 4 danios are eating and active. Twig catfish is doing great, not sure about the cories because they are shy and I can't count them easily but they come out and eat at feeding time at night (as long as I'm not too close).