Aquarium tanks vary by size. In order to build your aquarium tank lid to scale, you may need to adjust material lengths. Measure your aquarium before cutting materials, to ensure the aquarium lid fits securely. The lid build is based on a standard 20 gallon medium-sized freshwater aquarium that measures 24 inches-by-12 inches-by-16 inches.
Four ¾ inch-by-4 inch plywood boards, Four ¾ inch-by-3/4 inch square rods, 5/8 inch plywood, Three 1” molding pieces, White paint, Three hinges, Hammer, A handful of 16d box nails
Build the Support Box
The rectangular support box securely slips over your aquarium’s lid. It’s the frame work for your canopy. For a 20 gallon aquarium, you’ll want to cut 2 of the plywood boards between the lengths of 24 ¼ inches to 25 inches. It’s essential that the support box is a slightly longer length measurement than the top of your aquarium, as this will allow the box to slip over the tank. Cut the other two plywood boards between the lengths of 12 inches and 12 ½ inches. Finally, finish the rectangular box by nailing all four pieces together.
Attach the Square Rods
Three square rods are going to horizontally line the interior of the support box. They act as a break for the canopy top, so the lid can be lifted and lowered without landing in the water. Attach the square rods about ¾ inch above the bottom of the support box on 3 of the box’s 4 sides. Attach the final square rod vertically to the side you consider the back of the support box. For example, if your aquarium sits against a flat wall, the back of the support box will be the side against the wall. This is also where the canopy top will be secured, allowing the canopy to open from the front.
Cut the Canopy
The canopy, or the lid, will need to be measured to fit securely over the support box. Using the 5/8 inch plywood, cut the lid. The lengthier sides should be around 25 inches. The shorter sides should measure around 12 ½ inches. Attach the 1 inch molding to 3 of the 4 sides, using a hammer and nails. This molding is used to block light from leaking out, so attach it where it’s most needed. Do not attach molding to the back of the lid, where the canopy will be secured to the support box.
Paint the Box
Painting the interiors white will help improve light reflection. If you’re hoping to save on time, you can paint only the interior of the aquarium lid. Painting the entire thing is only necessary for aesthetic purposes. Allow the paint to dry completely before moving forward.
Attach the Canopy
Using the hinges, attach the canopy to the support base. Place the hinges an equal distance apart, along the back of the aquarium lid, ensuring there is enough support all the way across. If your aquarium lid measures 24 ½ inches, hinges should be placed every 12.25 inches. At this point, your aquarium lid should open and close. You can now place it onto your aquarium.