This thread is on my mated pair of yellow tail blue damsels . I need a place to write down my observations and document mating behavior of yellow tail blue damsels. This will with help blue damsels keepers my damsels are mature I would says 3-5 years old now. I have observed the blue damsels do their ritual dance of coupling and dancing around every now and then. Today was a real shocker to me . Today I did my usual monthly 5 gallon water change . my temperature was about 77 F. which is normal. I did my water change typically my water change is very quick 5-10mins. with water change complete. I looked over my tank and I noticed that one of the blue damsels was showing highlighted tiger like Marking s on his or her body. the damsels started kinda like prancing around the only I can describe it and the 2nd damsel proceeded to do their ritual damsel dance they both barrel rolled into my plating chalice . this behavior went on for about two mins. the surprise was the crazy color change on the blue damsel it was amazing It looked like it was glowing in white tiger stripes and the back of the tail was white. unfortunately I didn't record it plus I dont think I would have been able to record it. I realized the water change triggered this mating behavior in the damsels . ill post pics of the damsels soon . thanks