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How to Build a Lid for an Aquarium

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While some hobbyists forgo aquarium lids, others consider them indispensable tank accessories. Aquarium lids help to prevent fish from jumping out of tanks as well as help to maintain some thermal stability and slow the rate of evaporation. Aquarium lids are readily available commercially, but many aquarium hobbyists build their own. By using a sheet of acrylic, rather than glass, you will allow much more light to penetrate into the tank.

Step 1

Use a tape measure or ruler to measure the rim of the aquarium. Be careful to measure the outside dimensions, as the lid will cover the rim on all sides.

Step 2

Draw an outline of the aquarium rim on the acrylic with a permanent marker or a felt-tip pen, using the straightedge as a guide. In practice, the markings should be on the protective film covering the acrylic and will come off when you are finished and remove the film. If the film is missing, use masking tape to cover the general area where the lines will go, then draw the lines on top of the tape.

Step 3

Use a jigsaw fitted with a plastic-cutting blade to cut alongside the black lines. It is helpful to have someone help you support the plastic while you are cutting it. Always wear eye protection when cutting the acrylic pieces.

Step 4

Gently sand the edges of the acrylic with medium-grit sandpaper to achieve smoother edges. Keep your eye protection on while you smooth the edges.

Step 5

Place the lid on top of your aquarium and ensure that the size is right and your corners are square.

Step 6

With the lid still on top of the aquarium, use the pen to mark the inside border of the aquarium lid and the location, size and shape of any implements that must pass through the lid. These may includes electric cords for heaters, filters or pumps, as well as on-tank filters or air tubes.

Step 7

Remove the lid from the aquarium, and use the jigsaw to cut out the necessary sections so all cords and devices can pass through the lid.

Step 8

Sand the edges of the new holes to make them smooth.

Step 9

Cut the acrylic dowels with either of the saws so that they fit inside the black lines. These will keep the lid stable and prevent it from sliding off the aquarium.

Step 10

Flip the lid upside down and use the silicone to attach the acrylic rods to the lid. Place them inside the black lines that indicate where the inside of the lid will be. Use clamps to hold them in place, and let them dry completely.

Step 11

Once the rods fully cure, flip the lid over and ensure that the rods fit inside the inner aquarium rim. Make any adjustments necessary to achieve a snug fit.

Step 12

If the lid fits securely and accommodates all of your external devices, you are finished. Remove the protective film, if it's attached, and place the lid on your aquarium.