Had this Clown knife about 8 months now i think, he was tiny when i got him and was in my 20g then a 3ft tank and has been in my 120g for a couple of months now. He has shot up in size since being in the larger tank. Ive had a couple before over the last 20 years and they are possibly the best fish I have had. Unlike the last one I had few years back he is very active and feeds extremely well . Without a tape measure hard to say but hes probably about 12 inches now and getting the lovely hump these fish get and has all his markings which look better now hes bigger than when smaller