No silverfish/blue streak yet.i have seen smaller ones that do have it. From my understanding that streak is related to stress or emotions of the tang. I assume since mine grew up for 3 years with the same two fish and the environment has gone unmolested, that maybe that's why the streak hasn't developed. I recently removed the leapord wrasse, or I should say she removed herself from the tank. So now it's the black tang and a black occelaris clown. The leapord is alive and well though in my larger tank. That's were the black tang is heading very soon. I will keep you updated about the streak. I prefer not to see it, but I know it will show up one day. How did you score it for 250? That's what the hybrids go for around me.