Those glowlights are now more than 2 years old. They were in the hospital tank just after I tore down the 58 gallon and set up the 70 gallon in early august. I don't recall when I put them in the 70 gallon (maybe late august?), but I'm guessing the change from the neutral water of the hospital tank to the acid water of the CO2-supplemented 70 gallon prompted them to spawn. They did seem a lot more perky than they had been in the over-grown 58 gallon, but I just attributed that to them finally having room to move. Who knew that love was in the air (or water in this case)!