I am wanting to add a yellow tang to my tank. I see that swf.com has them for a GREAT deal. I have never ordered any fish from internet. I wanted this to be the last fish added to tank, right now only have two false perc. clowns. I passed on the order last week for 14.99 and don't want to miss out on the deal for 17.99. Are these fish on sale for this cheap on a regular basis? I know that it will not be on sale tomorrow. What to do?