Blue Emperor Tetras are amazingly fun fish to keep, they are always active, add plenty of movement to the tank, and are very interesting to observe acting out their natural behaviours.
They are a great addition to community setups or planted tanks, and are one of our personal favourite tropical fish.
But is it possible to incorporate them in a coldwater aquarium? Do you need to keep Blue Emperors in a heated tank? What temperature do Blue Emperors need to be kept at and why?
To find out, continue reading this article;
Can Blue Emperor Tetras live in cold water?
No, Blue Emperor Tetras are tropical fish, and need to stay warm if they are to survive and maintain Homeostasis, which is to keep balance in the body.
If kept in coldwater, Emperor Tetras cannot function properly, simple things like digesting food, and maintaining proper organ functionality will no longer be possible.
The fish will eventually die if exposed to waters too cold for too long.
Can Blue Emperor Tetras live in a tank without a heater?
It is in some cases possible to keep Blue Emperors without the use of a heater, especially if you live in a warm climate.
However, for most people, room temperature isn’t enough to keep Blue Emperors happy.
These fish like to be warm (around 26C / 78F) so unless you keep your house roasting hot all the time, it is advisable to install a heater to the aquarium.
How long can Blue Emperor Tetras survive without a heater?
Depending on the surrounding temperature, your Emperors may survive many months, many years, or a matter of hours without the assistance of a heater.
If the surrounding temperature is warm, and similar to that of the Emperor’s wild habitat, then it may just keep the tank warm enough for the fish to stay happy and there may be no use for a heater.
However, we would still suggest having one on hand as a safety measure, just in case there ever comes a sudden cold spell, which causes the tank to drop below the recommended temperature range.
In colder areas, a heater may always be necessary, as a cooler room may regularly cause the tank to drop in temperature, so it is best to have one at all times, just in case it gets too cold for the Emperor Tetras.
Why do Blue Emperor Tetras need a heater?
Blue Emperors are found in warm tropical waters in the northern areas of South America, close to the equator, where it is hot for the majority of the year and generally stays over 23C / 74F.
Because they are used to living in conditions like this, when confronted with cold temperatures of temperate areas, they can suffer from health problems, and cannot survive if the water is too cold.
It is important that a heater is used to prevent this, and so that the conditions of the fish’s natural habitat can be mimicked, ensuring the best possible welfare.
What temperature should a Blue Emperor Tetra tank be?
Blue Emperors like to be kept warm, it is typically recommended to keep them at anywhere from 25C / 77F to 28C / 82F.
Although they can live outside of this range by a couple of degrees, these recommendations are what the fish are most comfortable at, and should be aimed for in a community setting.
From our experience, we find that Blue Emperors generally prefer to live at around 25C / 77F and will begin to spawn at 27C / 80F.
Types of aquarium heaters for Blue Emperor Tetra tanks
The type of aquarium you keep your Blue Emperors in, will determine how you go about heating the tank.
The tank size is significant when it comes to choosing the right type of heater, but how do you go about selecting the right equipment for your Blue Emperors?
Choosing the right size and type of heater is fairly simple for most people, as many can use glass aquarium heaters, due to their versatility and availability in all different sizes.
To choose the right size heater, simply look at the wattage, it needs to match that of the literage of your tank.
For example; if you have a 100 litre aquarium, you should use a 100 watt heater, and so on…
Place the heater in the tank or sump and fully submerge it.
For the best effectiveness, stick it to the back of the tank or suspend it at a 45 degree angle.
For larger tanks, upwards of 500l, it may be more ideal to use a titanium heater, which works much the same, but has a much more powerful heating output.
These heaters are best placed in a sump tank along the bottom of the glass, next to the return pump, so that it may heat the water before it re enters the main display tank.
FAQs about heating Blue Emperor Tetra tanks
How do you test the water temperature in a Blue Emperor Tetra tank?
Testing the temperature of the water is fairly easy, there are all different methods to do it; you can use thermometer tape that sticks to the outside of the tank, glass thermometers which sit in the water, digital display thermometers which stick to the glass, probes or pens.
Our recommended method is to use digital thermometers since they are the most accurate and easy to read of all.
We personally prefer using TDS meters to determine the temperature of aquariums, as it is an easy way to get a quick and accurate reading.
The meter works by placing a pen into the water, and reading the heads up display, which shows the total dissolved solids and the temperature.
They are highly accurate, and very durable, allowing you to quickly test multiple aquariums within a short span of time.
Do Blue Emperor Tetra fry need a heater?
Blue Emperors need to be kept warm in their early stages, as they are highly vulnerable to temperature dips due to their small size and lack of fat reserves.
It is advisable to keep your fry tank heated at around 26C / 78F consistently if you are to ensure the best survival success for the fry.
What happens to Blue Emperor Tetras if the water is too cold?
Since Blue Emperors depend on their surrounding environment to control their body temperature, once things get colder than they are normally used to, they begin to struggle.
To avoid succumbing to shock, most fish will slow down their bodily processes to cope with the change in temperature, their metabolic rate and normal homeostatic functions will slow, preserving energy for when times are tough.
Blue Emperors however, as used to living at tropical temperatures, and while they can slow down their bodily processes for mild cold spells, they cannot enter an effective state of torpor to endure freezing temperature drops like coldwater fish do.
Being subjected to cold temperatures for too long will cause internal damage to the Tetras, they will suffer from organ damage, and will eventually die, unless the water warms up again.
What happens to Blue Emperor Tetras if the water is too warm?
There is also such a thing as too warm for Emperor Tetras, and if subjected to hot temperatures for too long, they can suffer greatly from internal health problems.
Heat stress is just as deadly as being too cold, affects them by increasing their metabolic rate and raising their activity levels.
Heat also changes the water chemistry and makes it more difficult for oxygen to dissolve, you may see your Tetras gasping at the surface for air.
Your fish will also become very uncomfortable and aggressive at warmer temperatures, as their increased activity levels cause them to be more irritable.
Once the water reaches higher than 32C / 86F the fish will begin feeling the effects of heat stress and if kept at such high temps for longer than 24 hours, they will suffer from organ damage, and will eventually die if it continues to get warmer.