Active aqua shop manager teaches how to deal with high water temperature in aquariums in summer! This year's heat wave is perfect!

Summer in Japan is getting hotter and hotter year by year... Measures against the heat of the aquarium are essential!

Measures against high water temperature in the aquarium are essential!


Compared to 20 or 30 years ago, summer in Japan is much hotter than before. As the outside air temperature rises, so does the water temperature inside the tank.


If the temperature inside the aquarium rises and goes out of the optimum temperature, it is a big problem that can affect the life and death of the living organism. So this time, I will talk about how to lower the water temperature of the aquarium. Please use this as a reference for measures against water temperature this summer.


5 ways to deal with the heat of the aquarium, taught by a shop manager with 25 years of aqua experience

I will explain what kind of heat countermeasures there are for the aquarium, citing specific methods.

Heat countermeasure 1. Use a fan

Fans are also effective in dealing with high water temperatures in aquariums.


Open the lid of the tank and use a fan to blow air toward the surface of the water. Then the water in the tank evaporates, but the heat of vaporization causes the water temperature to drop.


With this method, from the water temperature before applying the wind -2 to 4°CYou can lower it, but sometimes this level of lowering is still not enough. In that case, please use another method or select another method.


As for the fan, an aquarium fan is fine, but if it can blow air onto the surface of the water, you can use a fan for humans or anything else. It is important to keep the water level slightly low from the beginning, as living organisms are more likely to jump out if the lid is not placed. It is safe to lower the water level by about the full length of the living body.


again, Be careful not to let the water level drop too much due to water evaporation.. If the submersible pump and aquatic plants are exposed to the air due to a drop in water level, the submersible pump may break or the aquatic plants may die.


Be sure to check that the fan is firmly installed so that it does not fall into the aquarium. Also, the metal parts of the fan may rust, so be careful.


Countermeasure against heat 2. Use a cooler

Lower the temperature of the room itself with a cooler when the water temperature of the aquarium is high


If you can't lower the water temperature to the desired temperature with just a fan, cooling the entire room with an air conditioner is extremely effective.


If the room temperature drops, the water temperature in the aquarium will also drop. In addition to that, it is easier to lower the water temperature by blowing the cooled air from the air conditioner onto the surface of the water with a fan.


In this case, be careful not to overcool. It is safe to use the fan with a reverse thermostat (reverse thermostat) because it may be too cold if you use the cooler and the fan together.


An inverse thermostat is a thermostat that operates when the water temperature is higher than the set temperature. This reduces the risk of overcooling.


By the way, it is more efficient to control the heating and cooling of the tank with air conditioners in each room, so if possible, it is desirable to have the tank in one room.


In addition to air conditioners for rooms, there are also coolers for aquariums. In the next section, we will discuss aquarium coolers.


Heat countermeasures 3. Use an aquarium cooler

As a product for measures against the water temperature of the aquarium, there is also something called an aquarium cooler. This is an excellent product that can pinpoint the temperature of the aquarium even if the room is hot, but if the temperature in the room is too high, an aquarium cooler with a capacity that is just barely enough for the aquarium can lower the water temperature to the desired temperature. may not be possible.


Considering such things, Choose a powerful aquarium cooler with plenty of capacityis also recommended. Even if you make a mistake, do not choose an aquarium cooler with a small capacity for the aquarium.

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On the other hand, aquarium coolers are concerned about noise and exhaust heat. I think that some people in general households are concerned about the sound that the aquarium cooler makes when it operates. However, noise will not be a problem unless the aquarium is installed in the bedroom.


Even in the bedroom, if the room is cooled by the cooler when people sleep, the aquarium cooler will not work as much in the first place. Exhaust heat is the same as sound.

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Heat measures 4. use frozen plastic bottles

Frozen PET bottles are a countermeasure for high water temperature tanks!


As an extra, there is a method of lowering the water temperature by putting water in a plastic bottle, freezing it in a freezer, and floating it on the aquarium to cool the water in the aquarium.


Keep some frozen PET bottles ready at all times, and keep the water temperature constant by relaying the melted PET bottles.


However, the disadvantage is that there is a risk that the water temperature will drop too much and that there is a risk of a relatively rapid change in water temperature.


Even if the water temperature drops too much while no one is at home, the frozen plastic bottle cannot be removed, and if it cannot be replaced with a new frozen plastic bottle, the water temperature will rise again.


Water temperature changes in such a relatively short period of time put stress on living organisms and also create the risk of disease outbreaks. If you do this method, you need to try it a few times to get a feel for how it feels in your aquarium environment.


I haven't heard of any noticeable failures from actual aquarists, so if you really have to, try this method.


Heat measures 5. do a water change

Water change is also effective for high water temperature countermeasures


This method is similar to the frozen plastic bottle method above. Disadvantages are especially similar. The timing of the water change depends on the individual, but if possible, it is better to change the water when the water temperature has risen to some extent.


The way to do it is to change the water with cold water that does not interfere with the living body as much as possible. Cold water will force the water temperature of the aquarium to drop, so the water temperature change in a short time is a big disadvantage.


Depending on the temperature of the cold water used for water changes, the amount of water changes will change depending on the temperature of the cold water, so it is necessary to try it many times while watching the water temperature gauge.


The advantage is that water quality deterioration can be prevented by changing the water. Like the frozen PET bottle I mentioned earlier, it may be better than letting the heat kill the living body.


By the way, there is an aquarium saying that there is no filtration better than a water change, so keep that in mind.


Aquarium fish that are resistant to heat / Aquarium fish that are weak to heat

Now let's change our perspective and turn our attention to the living body. Let's keep track of ornamental fish that are resistant to heat and conversely, ornamental fish that are not good at heat.

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Ornamental fish resistant to heat

Garra Rufa

Water temperature upper limit: 37℃±

Fish resistant to high water temperatures


The highest water temperature Garra Rufa can withstand is 37°C. In fact, there may be cases where the fish died when the water temperature was lower than this, or on the contrary, they were alive when the water temperature was higher.


If the water quality and oxygen content are good, they will live, and if they are bad, they will die. This is true for all living organisms. By the way, the doctor fish in the footbath will be this species.


Water temperature upper limit: 35℃±

Discus is also a fish that can withstand high water temperatures.


Juveniles are generally kept at 31-32°C. Discus is a tropical fish that can withstand temperatures up to 35°C, as there is a way to treat anorexia by raising the water temperature to 34-35°C.


Garra Rufa is more tolerant of high water temperatures, but Discus, the king of tropical fish, is a fish that can be said to be a representative species of high water temperature breeding in the tropical fish world. The higher the temperature of the water, the less oxygen can dissolve in it, so adequate aeration is recommended.


Water temperature upper limit: 35℃±

Goldfish are also highly tolerant to high water temperatures.


Goldfish generally have a lower water temperature than tropical fish, but if you develop a viral disease called goldfish herpes, you can treat it by raising the water temperature to 33-35°C. Goldfish can adapt to a wide range of water temperatures.


From such a thing, it is natural, but it is also possible to mix goldfish and tropical fish. There is no big difference between goldfish and tropical fish, and if you install a heater with a thermostat, you can make them swim together.


Ornamental fish sensitive to heat

japanese freshwater fish

Water temperature upper limit: 20-30℃±

Fish that live in cold water should be careful of high water temperatures


Even if you say Japanese freshwater fish, there are many species that inhabit a wide range from north to south in Japan, from upstream to downstream of rivers, so it is not possible to say this unconditionally, but especially char that lives in the upper reaches. Yamame trout belongs to the category of cold-water fish, and since they live in cold water, the upper limit of the water temperature in which they can grow is low.


In addition, you have to be careful about the amount of dissolved oxygen, so you need to supply enough oxygen.

Ebi (shrimp)

Water temperature upper limit: 27℃±

Shrimp should be careful of high water temperature


In addition to Yamatonumaebi shrimp, there are improved varieties such as Minaminumaebi shrimp, Bee shrimp, and Tiger shrimp, as well as Algerian lime shrimp, Indian green shrimp, Sulawesi shrimp, and more.


It can be said that it is a situation where the water temperature is about 27 degrees Celsius and it can die at any time. It is a representative species that is difficult to keep in summer.

Saltwater fish (including sea anemones and corals)

Water temperature upper limit: 24-28℃±

A cooler is essential for aquariums with corals and sea anemones


Marine organisms are basically not good at high water temperatures. Many types of fish are still tolerant, but invertebrates such as sea anemones and corals are definitely not good at high water temperatures, and in aquariums where there are many such creatures, installing an aquarium cooler is basic.


This is one of the reasons why saltwater fish breeding is a little more difficult than freshwater tropical fish breeding.

Wooper looper (extra edition)

Water temperature upper limit: 27℃±

Wooper looper is strong against low frequencies but weak against high temperatures


Although it is not a fish, as an extra, Wooper looper is also a creature that is vulnerable to high water temperature. I think that there are many opportunities to see Wooper loopers because they are often sold at aquarium shops, but their properties regarding water temperature are very similar to shrimp.


It is very strong in low water temperature and weak in high water temperature. Wooper looper can also be said to be a representative of organisms that are vulnerable to summer heat.

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Let's take measures against the heat and overcome this year's heat wave!

High water temperature measures are important in hot summer!


What did you think. Along with water quality and quantity, water temperature is an important factor in breeding and managing ornamental fish. By knowing and managing water temperature, you can control not only growth but also reproduction and longevity.


Water temperature is closely related not only to fish, but also to microorganisms, fungi, and dissolved oxygen in the water, so be sure to acquire knowledge.

What is water temperature countermeasure in hot summer

ABOUTwho wrote this article

I am the manager of the small shop "Aqua Shop ZERO" in Kitaakita City, Akita Prefecture. I like discus the most and I love breeding. I think the best way to enjoy tropical fish is through breeding. If you can't write it in the article, please read it on our blog or LINE. Leave your worries to a professional. Thank you very much for your support.