Changing mouldy test tubes

Changing mouldy test tubes

I’m often contacted by panicked ant enthusiasts, worried about the appearance of mould in founding chamber test tube set ups.  Fear not! I’m writing this blog post to let you know when it’s time to worry about mould, and how to do a test tube change when it’s needed.

First of all, take a deep breath. It’s OK. Mouldy test tubes aren’t typically an urgent issue, and occasional test tube changes are relatively easy to manage. When deciding when to do a test tube change, I take into account the stress that the queen will experience.  Shifting a young colony from one founding chamber to another is a big deal for a queen, and not something you want to unnecessarily impose on her.  Therefore, I wait until the mould is quite significant before embarking on a test tube change.

Here are some examples of how bad I let the mould get before changing tubes:

Mouldy tubes.jpg

My approach to setting up tubes is low key. I use tap water, because I live in a suburban area with access to treated, clean tap water. If your house only has rain water, I’d recommend boiling or filtering. I highly recommend washing your hands well with soap and water before setting up tubes. Hands are gross!

The amount of mould that accumulates in tubes seems to be associated with the cleaning habits of the species. Pheidole are a notoriously messy bunch, and it’s not unusual for their tubes to have mould issues after only a month or so.  For most species kept in dark, warm conditions, I find three months is pretty average.

Steps for undertaking a test tube change are:

1.       Wash your hands.

2.       Decide which size tube will be best for your colony’s next home. I start smaller species in 16mm test tubes, and transfer them into 20mm tubes when their population grows to the point that it becomes tricky to feed them in the 16mm tube.  Your ants will be most comfortable with minimal territory to patrol and protect, but you obviously don’t want to be contending with escapees at meal times!

3.       Set up a new test tube. See my how-to video here

The new tube should be one third water, plugged with cotton wool.  The cotton wool needs to be fully inserted into the water, so that the ants have access to moisture.  I use a chop stick to push in the cotton wool.  I then wrap the chop stick in a tissue and wipe out the inside of the tube, to make sure it’s not too wet. Excess moisture can be a drowning hazard.

4.       Connect the mouldy old tube to the freshly made new tube. This can be done in several ways:

-          If you’re the kind of ant keeper who loves to have all the cool tools, here at Ants Everything we’ve developed test tube connectors to make changing test tubes very easy. They feature ledges to support the tubes and internal o-rings to cushion the connection. To purchase go to

-          Another option is to use clear PVC tubing. PVC tubing can be found at your local hardware store. Be aware that test tubes are measured with reference to outside diameter, while PVC tubing is labelled with reference to inside diameter. 16mm PVC is perfect for 16mm tubes and 19mm fits over 20mm test tubes – it has a little bit of give in it.

-          If your colony is advanced enough to be attached to an Ant Everything outworld, offering them a new test tube is a simple as connecting the fresh tube to other other end of the outworld! Your outworld would have been supplied with two open grommets and a closed one.  Adding a second tube is as simple as switching out the closed grommet for the open grommet and inserting the new test tube.


 5.       Place something over your newly made test tube to keep it dark and therefore more appealing to your colony. I typically just use a tea towel. Alternatively, you can encase the tube in alfoil or hot water pipe insulation (as shown in the above picture).

6.       Shine a light on the old test tube to encourage the ants to seek out the darkness of the new tube. I use an LED desk lamp, as it doesn’t use much electricity, or get hot.

7.       Be patient!  It’s not unusual for ants to take days to decide to move. It’s also not unusual for them to partly move, and then move back again, before finally deciding to move for good! They’ll get there.

​​​​​​​Hibernation and warming your colony over winter

Hibernation and warming your colony over winter

I’ve been getting quite a few questions lately about hibernating or warming ant colonies during the Australian winter.

Unless you live in the snow fields, you don’t need to hibernate your ants like some overseas ant keepers do.  As long as your ants aren’t facing sub zero temps, hibernation is not required.

During the cold months here in Australia, our queens and colonies will slow down egg laying and activity. Laying fewer eggs and moving less than usual will mean they require much less food. Less activity= less fuel for energy required. So don't be alarmed if they go off their food.

Heating is not required, but if you want to heat your colonies, it will reduce their winter slow down. 

If you are keen to pursue warming, I recommend you only warm over their first winter. I feel it is beneficial to your queen to get her first lot of workers (nanitics) hatched so that they can look after her and take on the brood care duties.  However, in subsequent winters, I recommend not warming her, so that she can have a break from constant laying. She needs a holiday just like us, and the theory is that these breaks prolong her lifespan, too! 

To heat your queen through her first winter, I suggest using a heat cable (15W x 3m) stuck to a shelf (or similar) with blu tack. Lay your test tubes down on top of the heat cable, with the cable close to the open end. Use more blu tack to prevent rolling.

Heating cable blog picture.jpg

Having the cable close to the end gives your queen flexibility to choose a warmer or cooler spot for her brood and herself.  Don’t place the tube at the water end to avoid creating excess humidity and, in extreme cases, a drowning hazard.

Keep an eye on your queens so that you can pick up on their cues about how comfortable they are in their living spaces. If winter is coming to an end and your queens stop using the heat cable, it could be a good indication they no longer need it.