The first time I paid any attention to my tank since before we left on our trip, I see three of these little guys. Totally didn't expect it. I mean I hadn't changed the water in 3 weeks or so. The last time I did, was right before the first good rain in a while. Perhaps that helped trigger a spawn. These guys are large for their age, but still relatively small. I was very excited when I saw the first one, and even more so when I saw the others. Maybe there are more in there, but I doubt it.