i had a 7 incher.for almost a year.he was great untill i added a couple corals with ich on them.he fought two rounds of hypo then didnt make it.i had a purple for 4-5 years i lost to the same ich.it was funny .the purple was 4 inches like half the size of the achilles.when i put the achilles in the tank the perple went at him and bit his behind.the achilles turned and looked at the purple like are you kidding me? that was the end of that.they got along fine. i never had a problem with him until the ich.when i get my bigger tank going i will get another one for sure