Jim - I think some or all is lighting. My bulbs in the 6G are over a year old. I just got a new bulb, but haven't put it in yet. Plus the Kenya Tree has grown so much in that tiny tank that it's starting to shade things. There's only about 3 watts/gallon of light in the 6G tank, and I have about 5 watts/gallon in the RSM. Plus the T5s are I'm sure higher quality in the RSM than the 18 watt bulb in the little JBJ tank. When zoas look like they do in my first picture it seems to indicate to me that they're stretching to try to get closer to the lights. Just my opinion on the stretching, but I even see it on some zoas in the RSM that are a bit shaded.