How to Lower the Temperature in an Axolotl Tank

Photograph of leucistic copper axolotl. Courtesy of Hal Hope.

While temperatures begin to heat up in the northern hemisphere as we head into the dog days of summer, maintaining control over your axolotl tank’s temperature grows increasingly important. Warmer weather can be quite the issue for some hobbyists, and this article will take a dive into the multiple ways you can keep your axolotls cool. ​ Thermometers

Without a thermometer, there is no way to reasonably determine the temperature of your tank. When it comes to thermometers, hobbyists have a few choices available. There are simple analog thermometers that use a tube of red alcohol, digital display thermometers with probes that sit inside the tank, and handheld laser thermometers (temperature guns). Although the analog thermometer may be simple, it is often quite reliable. Its simple design makes it easy to use, and the results it provides are generally accurate. Most analog designs rest on the rim of your tank and are submerged just below the surface of the water. In larger tanks where the water level is kept a few inches below the rim to prevent axolotls from jumping out, the typical analog thermometer may not reach the water. In this case, different analog thermometers or different types of models may be required.

Some analog thermometers will have "safe zone" marked on them. This marking is not relevant for axolotls and refers to the appropriate temperature range for tropical fish.

Digital display thermometers are a step up from the classic analog thermometer. These provide a detailed look at the temperature of your tank. However, some electronic display thermometers can be inaccurate. I personally have purchased some that were off from the true temperature by almost 6°C (10°F), so if you do use one, then be sure to purchase a backup thermometer to verify the accuracy. These thermometers may also decrease in accuracy over time. Another feature of the electronic display thermometer is their probe that can be submerged inside your tank. This allows for a potentially more accurate look at your temperature but also may attract the attention of curious axolotls that may mistake it for food. We have not had any issues with axolotls trying to eat temperature probes, but watch out for curious axolotls all the same.

Digital thermometers can provide a quick way to check your axolotl tank's temperature. However, this convenience can sometimes come at the cost of accuracy.

A very reliable, albeit an expensive, thermometer is a laser thermometer. Also known as temperature guns, laser thermometers are handheld thermometers that use a laser to report back the temperature of the surface they are pointed at. These thermometers are reliable, and are useful for hobbyists with several tanks. Laser thermometers are also convenient for temperature matching water during water changes or while acclimating new axolotls or cycled media to your tank. When using a laser thermometer, be sure to aim at the water itself from the top and not the tank wall as the glass will not give an accurate temperature for the water it holds.

Laser thermometers are easy to use and are great for people with more than one tank. If you use a laser thermometer remember to aim the laser at the water itself and not the side of the tank.

Cooling Methods ​ Now that we have gone over the various types of thermometers that you can use, we will discuss the various methods that are used to cool axolotl tanks in the summer heat. ​ Location The first step that you can take in cooling your axolotl is to consider the location of your tank. Be sure to avoid direct sunlight and keep it away from appliances, such as televisions, game consoles, and refrigerators. If your home has a basement, then that may be a great place for your axolotl as basements typically are the coldest place in a house. Air conditioning can be a great tool if you have access to it as well. Lowering the temperature in your home to around 21°C (70°F) makes all of the following cooling suggestions far more effective. If you do not have air conditioning, you can purchase portable air conditioners or window units to cool small rooms. Keep in mind that these are expensive, and still need a window or a door to vent hot air through.

Some portable air conditioners have built in dehumidifiers that can help increase the effectiveness of other cooling methods like fans. Photo courtesy of @loaf.

Cooling with Ice One of the most suggested methods on the internet for cooling an axolotl tank is by using ice. While this method may work temporarily, it is not the most efficient method of cooling and it heavily relies on the ability of the hobbyist to constantly be present to add new ice. Additionally, using ice in small bodies of water can rapidly cool the water immediately surrounding the ice and increases risk of temperature shock for axolotls that swim nearby. Cooling with ice or frozen water bottles is not a permanent solution to cooling an axolotl tank, but it will work in a pinch if needed. If you need to use this method, here is how to do it: 1. Find 2-3 disposable plastic water bottles, and rinse them out. Remove their label. Fill the water bottles ¾ of the way with dechlorinated water and twist the caps onto the bottles. 2. Once the bottles are filled ¾ of the way with dechlorinated water, place them into the freezer. 3. Once the water bottles are frozen, remove one bottle from the freezer. Place this bottle into your axolotls tank. 4. Once the frozen water bottle in the tank has thawed, remove it. Place the now thawed water bottle back into the freezer, and take out another frozen bottle to place into the tank. 5. Repeat step 4 as needed to keep the water temperature of your axolotl tank consistently below 20°C (68°F).

Despite being one of the most suggested ways to cool an axolotl tank, ice is also one of the least reliable methods. Other methods are far more consistent and effective.

Clip-On Fans A more permanent and effective way to cool your axolotl tank is with evaporative cooling. As water evaporates, it takes a small amount of heat away. Hence why perspiration cools the human body when it evaporates. One of the best ways to promote evaporative cooling is by utilizing clip-on fans that constantly blow air across the surface of your tank. This method is capable of lowering water temperature by as much as 3°C (~6°F). If you decide to use this method, be sure to watch your water level and add more water to the tank when needed. Using a fan greatly increases the evaporation rate of water, and you may need to top your tank off in between water changes. Keep in mind that fans will not be effective in places with very high humidity or when the room temperature is high. Another thing to consider is that not all clip-on fans are equal. Some work surprisingly well, while others may be noisy and ineffective.

Water Chillers Another effective, but expensive, method of cooling an axolotl tank is using a water chiller. Chillers are external devices that water is passed through and then subsequently cooled. As efficient as they are, chillers can be difficult for hobbyists to set up. In addition to purchasing a chiller, hobbyists will also need to purchase a pump or canister filter. This method is quite effective for those living in extremely hot climates without air conditioning, or for those that live somewhere very humid.

Chillers are the best way to maintain a constant temperature in an aquarium. Chillers may also be the only option for people living in hot, humid climates. Photo courtesy of illiam331.

Controlling the temperature of your axolotl’s tank is something that many do not consider until it is too late. As warmer weather approaches, it is essential to make sure that you have a way to accurately measure the temperature of your axolotl’s tank. When your axolotl’s tank rises to 68˚F (20˚C) or above, you must have a consistent way to cool and maintain suitable temperatures. Being prepared for this eventuality is essential avoid inducing stress in your axolotl.

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