Tank topper mods

Update October 2019: I no longer have any gerbils, and I sold both this tank&topper and a subsequent DIY tank&topper a couple of years back. However throughout the period where I wasn’t updating this website at all, this page has kept regular viewing figures. So I’ll leave it live in the hope that it’ll still help others.

I’ve now been keeping gerbils for a whole 3 weeks. However the three weeks prior to their arrival were also very full of gerbilly things as most of my spare time was spent making their set-up.

I knew from the outset that I wanted to provide them with a topper on their tank. Firstly because it’s nicer to interact with prey animals from their level rather than looming overhead. But also because although gerbils do dig tunnels as their home, they’re not solely an underground species. Thus finding a way to replicate their above/ below ground natural life was important to me.

Even though I was going to give them a tank topper somehow, I still wanted to put this on the biggest tank I could – with an enriched environment there’s not really any risk in going big, while I might have regrets if I settled on smaller. In my rodent/ spare room I have a solid oak desk (built by a school age uncle of all things) which is much less deep than desks are made nowadays. However with a little overhang at each end it would perfectly fit a 120cm (4ft in old money) tank, so that was my aim. And yes, I got lucky on the tank. Someone about 40 miles away was giving up a large fish collection, and so was selling off the tanks cheaply.

120cm tank

My aim was to give maximum space with minimal cost, and so rather than buying in materials to make the topper, I primarily moddeed bits and pieces I already owned. As I’m not particularly good at wood-based DIY I wanted to avoid any sort of design which included a wooden frame. As a result of both of these things, the front, back and roof of the topper are made from a Marchioro Tom62 cage which I had not currently in use. The purely coincidental measurements meant that two Tom62 panels would perfectly fit the tank length. Which also perfectly answered the question of how tall to make the topper, as it couldn’t be more than half the height of the Tom62 cage or I’d run out of materials.

Front, back and roof panels

There was the minor matter of the small 13cm door holes already cut out, however with just a little bit of careful arranging I managed piece things together in such a way that I’d be able to have mini doors with a 90° corner in them. All that was then left was for me to work out the placement of the larger ‘proper’ doors. I decided I would mod in a larger door on the right hand side of the front (for interacting with the gerbils), and have the full left hand side of the roof opening (for easier access in terms of toys and other enrichment). This sounds like a minor step, but it took bloody ages because of the time needed to individually file down 96-or-so small bars which had been cut.

This notebook became rather more scribbly after I took the photo

This was all well and good, except I still hadn’t decided what to do for the two end panels. As you can see in the notebook above, they weren’t quite square, which proved to be rather too awkward. After many ideas all of which went hideously wrong, I settled on using C+C squares with an overlay of some other doors I had lying around (have use previously for making pens for foster rabbits/ guinea pigs/ kittens). The squares themselves provide a lot of rigidity to the otherwise not-reinforced structure, and the overshoot upwards act as excellent built-in handles. However the gaps are too big for small rodents, hence the layer on top.

Double-layered end panel

The next stage for my plan was to repaint the cage. As I’d chopped up a pre-existing cage there were a lot of exposed bar ends which didn’t look very nice, and would also be at greater risk of rusting. Additionally while the Tom62 cage itself had started off a nice dark green, I’d previously touched it up with bright orange. And on top of that, the overlain end panels were two-tone blue from similar previous cage mods. Since I was making it again from scratch I decided a repaint was in order. Burgundy wouldn’t have been my first choice in colour if everything else had been equal, however it wasn’t (is it ever?), so that was the best fit all angles considered. I had intended to paint everything except for the two C+C end panels, however it turned out that I forgot to paint the large front door I added on. Of course I didn’t notice until much too late. At least the silveriness of the galvanised door matches the silveriness of the end panels.

Completed tank topper

As for joining the panels together securely, while I had been designing and building the structure itself I had used colour-coded pipe cleaners. However I didn’t feel that they were strong enough for the end result. Plus the fluffiness holds smells, and they didn’t look very neat anyway. For a while I considered using garden wire, as I use the stuff a lot for rodent cage things anyway. And while that would have been a viable option for most of the joins, it may have created a slight safety issue at the hinge side of the fully opening half of the roof.

Instead I decided to splurge some money on proper cage-building supplies. While you can buy J-clips and pliers in the UK, the cost of the pliers alone are more than the total cost of importing everything from the US. The wait wasn’t too bad since the newly painted cage had to air for a couple of weeks anyway so as to ensure that all smells had safely dissipated. The J-clips wrap fully around the bars without any sharp edges at all. They’re very rigid and strong for adding support, while still allowing some rotational movement for hinge joins.

Close-up of a J-clip

It would be a lie to say that attaching the J-clips was super easy. Some of the bars I was joining were slightly too thick as a pair. And it turns out that removing them is really super challenging and involves pliers and swearing. Why was I removing them? Well it turns out that putting the inaugural line of J-clips along the one bit of cage you don’t want them is a stupid idea. That line of the cage now has 4 mini bulldog clips instead. Because yes, that was the edge of the door that was meant to open fully. Everything works much better now that the main door isn’t firmly fixed closed.

Purchase costs

  • Tank, £20
  • J-clips and pliers, £23.30
  • Plastikote, £2.99
  • Paint brush, 30p

Total cost: £46.89

2 comments on “Tank topper mods

    • Thank you! I don’t know how much I’ll be explicitly posting about the gerbils, they’re sure to pop up at various times in the future.


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