This article is from the Summer I 1997 AFRMA Rat & Mouse Tales news-magazine.
By Nichole Royer
Be it at a garage sale, thrift shop, or swap meet, most of us will jump at the chance to buy a used aquarium for a very low price. These great potential rat and mouse homes often cost $2 or less for a 5 gallon, and great deals can be had on larger ones as well. Unfortunately, most of these either do not have a lid, or they come with glass lids unsuitable for use with anything but fish. This is where those “great deals” can quickly become expensive investments. Screen lids from a pet shop start at $10, and they do not allow much air exchange. The cheapest (and best) lids are ones you can make yourself.
Unroll a section of the wire mesh and flatten it out. Center it on top of your tank so that there is a 3 square overhang on all sides (4 square for anything larger than a 5 gallon). Trim off excess so that all four sides are flush and no points (prongs) stick out.
While holding the wire centered on top of the tank, gently fold down one long side of the overhanging wire (fold A). Use the top lip of the aquarium to fold against so that you get a tight, sharp edge. Repeat this on the other long side. This should give you a snug fit with overhangs at both short ends.
Cut along each end as shown in figure 1 (cut A). Leave prongs attached to the folded long side. Cut so that the prongs are as long as possible.
Make the second cut (cut B) on each unfolded short end. This cut should be flush with no prongs left behind.
Bend down the overhanging short end pieces using the aquarium edge to make the bend straight and tight.
Use needle nose pliers and bend the prongs from the long sides around the flush cut edge of the short end (Figure 2). This attaches the edges of the lid together. Be careful not to do this too tightly or you will not be able to lift the lid.
This is your finished lid. For mice nothing else need be done. For rats (or hamsters) you must add a heavy weight like a brick or large book to keep them from pushing the lid open.
The edges of this lid will be left with sharp bumps. If you are careful you can use the lid this way without problems. I always end up getting scratched or my clothes snagged, so I get rid of these bumps. One easy way to do this is to take a metal file and whisk away anything sharp. I have an electric grinder which works wonders at doing the same thing. You can also take duct tape and run it along the inside of the edge of the wire. Leave enough hanging off the bottom to fold over sandwiching the sharp points between the halves. This will need to be replaced periodically as it wears out.