I have had them for 5 months. They were 1 inch when I got them. I end up with pair, I guess. Female is a little less than 2 inches, male is 3. Female starts getting yellow recently but male still mostly attack her. When I add another female from different source male started divide his attacks among these two, female also attacks newcomer which turns almost entirely black. I guess my pair must be about 1 year old I hope they will spawn soon.