For 47 years he was an aerospace manufacturing engineer. He designed and built very complicated parts that went in planes and missiles. He was constantly making decisions about whether or not to buy expensive manufacturing tools, and the calculations usually came down to something called Return On Investment (R.O.I.). Our decision about the lights was sort of a miniature version of the decisions that he made in his work. 

He listened carefully to our explanations just as if we were talking about one of the big decisions that he had to make. We talked about the pros and cons, about the cost, about how the lighting would affect the quality of our fish and customer satisfaction. He emphasized that, although our numbers were smaller than the numbers he usually considered, the principles were exactly the same.

We analyzed the numbers with his help, and it seemed that we couldn't quite justify the cost of putting a light above each aquarium. Of course the numbers were just our best guess-timates and only an approximate guide in making a decision. 

Then our father said, "Whenever the numbers are close and only guess-timates, like these are, you have to exercise your insight. You say that you feel a light above each aquarium will definitely improve the quality of the fish. Quality is of course always important to your customers; they want good fish."

"Quality is also important to you, because improved quality usually leads to other improvements that will make your whole operation more efficient. You'll spend less time medicating sick fish, because you'll see problems sooner, take action sooner, and prevent even bigger problems."

"You will probably find out that the cost of the lights turns out to be justified. But right now investing in the lights is sort of an act of faith in your business. You should not just willy-nilly invest in every piece of equipment that might somehow turn out to be useful."

"But in this case, you've justified most of the cost, and experience shows that you, your fish, and your customers will probably benefit from improved quality in more ways than you now know."

"If you do add the lights, as I now recommend, then you should review your decision once every year to see if the cost was justified. In that way you'll check your decision, and begin to build up your ability to make these sorts of decisions when the numbers are close and you have to use your insight to make a judgment, and that is a very important skill."

We took his advice, installed the wiring and lights, and later reviewed our decision. He was right. There were unexpected benefits. Good lighting was an important factor in our superior quality, and encouraged us to invest in other projects to improve our facility.

You may think that this is a sneaky way to brag about the quality of our fish and convince you to buy fish from us. But I wrote this thinking about young people who are now about the age we were, when our father gave us this advice. If you're thinking about being in the fish business, you too could benefit from the advice our father gave us a long time ago.

I always make sure the light is on in the room, before I turn off the light above the aquarium, so my fish are not in the dark. The lights in the room provide a dim lighting for the fish.

Later I turn off the lights in the room, and the change is not so sudden, so the fish are not startled. I hope this information is useful to you.