Your BTA is becoming more bleached than it was in your first pics. They should not be translucent as the tentacles on yours are becomming. You need more light. While I agree with others that they do not always appreciate the most intense light, your light is very weak for this animal. If you do not get better light, the long term health of that nen is questionable. In the mean time, keep feeding it, as its likely the only reason it hasn't perished already.