A friend of mine had a breeding pair of Axolotls which had been together in the same 90 litre tank for well over a year. There were no other tank inhabitants. Last week he found that his female had been disembowled. The male was alive but most of his gills had been damaged. These animals were very closely monitored, There had been no sign of trouble as recently as 5 o'clock the previous evening. I had seen them myself 3 days before the event and they showed no signs of picking at each other then. I would really like to hear what other people think could have triggered this. Is it common for adults to fight to the death like that? Could it have been courtship behaviour gone wrong?