I have just bought a Purple Tang from the LFS. When they received it it had Lateral line disease. They kept the fish for me and it has done well. It has been 4 months now and I went ahead and bought it 3 weeks ago. It is doing great but still has the stripe on its back from the LLD. How long does it take for this to clear up. Is it a scar or is he still a little sick? Is it succeptable to reacuring if it is placed under stress?