I know theres alot of diy LED light online already so here's another..although this one is cheaper and less complex than most.
Required skills and knowledge: Basic soldering, cutting plastic with a dremel and basic electrical theory.
Step 1: Materials and Tools
Tools you'll need:
Soldering iron and lead to connect wires
Dremel drill with circular cutting disk.
110v LED bulbs $3 to $10 each(depends on how bright you want your fish tank)
6 to 9 ft Extension cord $1 to $2
Wall switch less than $1 *not required
PVC gutter 12 feet for $6.50
PVC gutter end covers $2.50 each
PVC 3/4 inch conduit clamps 5 for 76 cents *not required
* All materials except the LED bulbs was bought at Menards Hardware store.