I had my female and male alone in seperate tanks for about 2 years,,, i then consolidated tanks and put them together,,, its was tail swatting and bowing at first sight, lol. You jsut MUST make sure that the one you get is about half the size of your current one and if you have had her in the same tank for three years, try re-arranging some of the rocks when you add the male (and turn the lights out do it before the night cycle anyways so he'll have all night to get comfotable)