We got a small ACEI from petco. She was light dullish blue, but after being in our tank for an hour or so, she is really dark purple now. She is very active, swimming all over the tank. The labs didn't seem to care that she checked out the caves either. Her fins are showing a slight yellow now, but at the pet store they were clear. I can't seem to find an answer, but is this a sign she is happy and doing better than she was at the pet store?