Well,
Based purely on investment, growth, over all visual impact...and being an artist I have to gauge prices of "things" all the time...I would ask a given price, much higher than you expect but within what you know to be reasonable for the buyer.
You paid $40 for a couple inches of animal. You raised it with expensive lights, ultra clean water, speciallied food, unique equipment, mounted on established live rock, and do not forget your time and effort. All of this is an investment.
I personally would ask no less than $225.
It is a wonderful piece, with a strong history of good health and a proven track record of valued growth. It has a a significant impact and would make a fantastic showpiece.
And as it is a buisness that is interested, it is a write off for their taxes.
Maybe I am way off here, but I would consider it a reasonable offer. That way if they counter with an even $200, you are still a winner.
Just an opinion, no yelling please
Ray Boemler
www.peanutbutterjellyfish.com