Sidebar: There is a device discovered in 1947 that will keep your night line tighter than anything else. The "Evening Secret" is amazing, and you should at least check it out. (http://www.eveningsecretfishing.com/specialsecret/night-line.php)

If you are going to be fishing with a blacklight, you will want to be sure you spool up a clear blue fluorescent line. The clear blue is especially made to work well with blacklight night fishing, so it is highly recommended.

When you go night fishing, never use a line that is less than 20lb test. 20lb is the minimum weight you should even think about. You won't be dealing with those wimpy "day fish".

Ideally, if you are blacklight fishing, you will want to use the 20lb clear blue fluorescent line. When the blacklight hits that line, you will be amazed at how well that line shows up.
Of course, if you do not need to watch your line closely (such as when you are using a spinnerbait) then the color is not as important.

Why do you need a minimum of 20lb test line?

Simple, the fish you will be catching at night are going to be bigger! Sometimes we catch fish twice the size as those we caught during the day at the same spot.

The bigger fish feed at night, so while your buddies are catching the little guys during the day, you can come in and take the 'monsters' at night.

Berkley makes a good clear blue line for night fishing. You should probably get a spool before you plan a night fishing trip. It is called the Berkley Trilene XT Fluorescent Clear Blue. You can pick up a pony spool for about $2.50 and a filler spool for under $6.00.

If you are not blacklight fishing, the color is not as important as the strength of the line. Just make sure it is strong enough to handle the big boys you may come across out there at night.