Small Ant Nest with Swappable Connections

Hello! I designed this small ant nest with the ability to use it either standing up or laying down in mind. There are 2 entrances that use a screw-in system to easily connect to other things.

It uses 3mm bolts at 20mm long. Or 19mm if not using washers.

There's a small opening at the side for inserting a pipette to (slowly) fill the reservoir with water. The reservoir should be packed with cotton to hold the water. I use 2 cotton wool pads, but any cotton or sponge should do.

My colony is still too small to move in, so I haven't actually tested this with ants yet.

The test tube adapter has been made to fit into the glass 150x16mm test tubes that come with a Wakooshi nest. I'm not sure if other brands would be sized differently, but do let me know!

Tips for printing the cap with air holes:
In your slicer, disable top and bottom solid layers, and use a grid-pattern infill at 80%.

Tips for printing the tunnels with humidity holes:
You will need a slicer that allows you to set separate print settings for different objects on the print bed. I use Prusa Slicer.
Use the extra Tunnel Block files to get the combination you want, and set them to print in the same position. There's a rectangle border in these files to help position them correctly. For the floor piece that you want to have holes in, disable top and bottom solid layers and use a grid-pattern infill at 80%.

Tips for making the acrylic window:
I used a 2mm sheet of clear acrylic. I drew around a "Clear_Acrylic_Template.stl" print onto the sheet's protective paper as a guide. I snapped it roughly to size by scoring the surface with a knife and snapping off the excess on the edge of a table.
I then used a metal file to file down the edges and the rounded corners to the correct size. I then assembled the Outer Housing, Tunnel Block and the acrylic without screwing anything in. I flipped it over and used the screw holes on the back to guide a 3mm drill bit all the way through to the acrylic. Remove the protective paper from the acrylic and you're done! If your edges are a bit sharp and jagged, you can use a small, wet piece of 800-1000 grit sandpaper to gently smooth the edges. Be very careful not to sand the surface of the acrylic sheet, otherwise it will scratch.

Okay but why not make it easier and design it with squared corners?
I just think it looks nicer, and it's really not very difficult to file the rounded corners. Promise! Just go slow and file a bit at a time until it fits.