Mine has been black for a while. I used to have two, one male and one female. Then one day the male decided he could no longer live in captivity and went looking for greener pastures and only found my hardwood floor. Well after the female saw her hubby die on the floor she became real dark, almost pitch black to the point that you can not see her patterns. I thought that she was like that because she misses her man (which turned out to be right). A jag expert told me that jags, epecially females tend to be moody and if they are depressed or feel uncomfortable or if they get separated from a male that they have bonded with they will trun dark/black and sometimes when they are about to go into a growth spurt it can happen. He told me to try to make her more comfortable by giving her another male or rearrange the tank to see if it helps. I rearranged the tank and even though she is not normal yet, it does seem like she is trying to make a comeback.
