Aquarium thermometers are a small but essential item for your aquarium. If the thermometer breaks then it will not harm the fish. Top Fish Tank Thermometers Reviews. Zacro LCD Digital Aquarium Thermometer These little balls float on the alcohol and help you better see what temperature the tank is. Let’s start with a very affordable and basic digital thermometer like this one. The silver liquid is Mercury and can be very dangerous to a fish. Having a good thermometer to track your water's temperature at various times and days will help you identify and correct problems due to temperature changes. In a mercury thermometer, the liquid inside is silver. Here are some reviews of the best thermometers you can use: 1. Sometimes, such thermometers are simply allowed to float on the surface of the aquarium. Do a water change and remove all of the pieces of glass, and your fish should still love you. Alcohol models are dyed either red or blue. A mercury aquarium thermometer or similar form of non-digital thermometer can often be attached to the inside of an aquarium with a suction cup. 1. So, you just released alcohol in a VERY tiny dose into your tank. Yes, thermometers are required at household for more than just figuring out whether you are suffering from fever or not. Depending on the species of fish, there may be varied temperature requirements as well. To make your job easier, we have picked the best aquarium thermometers you can buy online right now. TOOGOO Digital LCD Thermometer. Now is when you take a deep breath, because you have the alcohol model. 6 Best Fish Tank Thermometers to Buy in 2020 1. If you have an aquarium at your home, then you will need to get yourself an aquarium thermometer because maintaining the right temperature of the tank water can be the difference between the life and death of your aquatic pets and plants. A standard thermomater has mercury in it, ive no idea whats in an aquarium thermometer but i would play on the safe side and remove the axolotl and do a 100% water change. Digital thermometers, mercury thermometers, and other forms of thermometers can all be used in aquariums. It offers a 25mm X 12mm LCD screen, with a 1-meter cable connecting it to a … The silver or black balls or made out of the lead. Although the tank may look fine, changing or unsuitable water temperature can have a negative effect on both fish and plants. Older thermometers and some laboratory grade thermometers contain silver liquid.