Tetras are one of my favorite fish. They’re an easy fish to raise and generally live a peaceful existence.
This makes it quite said when they die an untimely death. They can die for a variety of reasons, but the most common reasons tetras die a premature death include poor water parameters, bullying from tank mates, sickness, and stress.
This article will cover the six most common reasons that your tetras die. Knowing these reasons will hopefully allow you to ensure that your tetras live a long, healthy life.
Note: The list is in no particular order.
1. Cold Water
Tetras are a tropical fish that like water between 75F and 80F. They can live in a water a little colder and water that’s a little warmer. They cannot, however, live in colder water like that required of a goldfish.
However, many tetra owners that live in cold climates run into problems during the winter. This problem can be mitigated with a relatively inexpensive aquarium heater.
It can still become problematic if the heater breaks or the power goes out (ie. during a blizzard).
Tetras won’t live long in cold water, so I recommend running a two heater setup in your tank in case one breaks. If the power goes out, then you will have to figure out a way to keep the fish tank warm.
I recommend keeping the tank near your fireplace or another warm area in your house.
Stress is the most common reason that tetras, and all aquarium fish in my experience, die. It has a wide variety of causes. The most common reasons that tetras get stressed are cold water, overcrowding, living without other tetras, and bullying.
A stressed tetras will not eat much, hide in structure, and erratically swim up and down the wall of the tank like they’re trying to escape.
It’s not difficult to spot a stressed tetra.
The easiest way to calm a stressed tetra down is by solving whatever is stressing them out, which should be fairly apparent once you realize the three main causes of stress.
Tetras are a schooling fish that require room to swim around the tank. They will get stressed out if they don’t have room to swim around.
I recommend a 20 gallon tank at an absolute minimum if you want to have neon tetras. But bigger is always better, especially if you plan on having other fish in the tank.
You can tell if your tank is overcrowded if the tetras don’t swim around much OR they get in fights with other fish.
An overcrowded tank will also have poor water parameters or require frequent water changes, which is what actually kills the fish.
4. Poor Water Parameters
Water parameters refer to the quality of the water and other basic properties (temperature, pH level). Every fish thrives in certain water parameters and cannot live in water that has too many toxins in it.
They can even die from the toxins in super glue if and only if you use still wet super glue in your aquarium.
For one, your tank should have low levels of ammonia, nitrate, and nitrite. This can be accomplished by not letting food rot in the tank and vacuuming up any of the waste that the fish produce.
Tetras also need a pH level of 6.8 to 7.8 to thrive, which is pretty standard for most fish.
Anyway, you can ensure that you have the proper water parameters by doing a weekly water test. If anything is out of whack, then corrective measures can be taken to restore the balance.
5. Water Temperature Swings
Tetras are a hardy fish that can survive a far wider temperature range than many people believe.
However, they cannot survive a rapid change in water temperature. The usual cause of a rapid water temperature swing is from an improper water change.
Basically, aquarium owners will do a 50% water change all at once without ensuring the water is the same temperature as the water in the tank.
One, you should move the fish to a separate tank when doing such a big water change. If you can’t move the fish to another tank, then make sure the new water is the same temperature as the water in the tank.
6. Aggressive Tank Mates
Tetras are a small, peaceful fish.
This can make them a target of bigger, more aggressive fish.
You really have to ensure that you don’t have any aggressive fish in your tank with neon tetras as the tetras will simply be a target for the more aggressive fish.
Now, you can have more aggressive fish in a tank with tetras, but you will need a very large tank and plenty of structure to ensure that the tetras have room to stay away from the other fish.
Tetras are a schooling fish. You cannot have tetras in a tank alone.
They will literally die if left alone as the fish do not know how to function without a school.
I recommend having at least 6 tetras per tank. You can maybe get away with 4, but I really recommend six for maximum health.
Again, the more tetras the better. Just make sure that you have a big enough tank and a good enough filter to handle all the tetras.
Tetras are a relatively hardy fish, but they can still get sick or diseased from a variety of things. Most disease outbreaks in aquarium are a result of poor water conditions that weaken the immune system of the fish.
Disease can also be introduced by adding plants or other fish to a tank.
You can spot a diseased tetra just by looking at it. They will often have something wrong with their appearance (ie. duller colors, fin rot, or white patches).
Once you figure out the disease, then the fish can be quarantined if necessary and the appropriate medicine can be used to treat the disease.
You also want to check out your water parameters if you notice a sick fish. Fish in high quality water rarely ever get sick!
9. Old Age
Finally, tetras can die of old age if you take care of them properly. A healthy tetra should live 5 to 7 years in a fish tank. They can live up to 10 years in nature, but that’s sort of rare as they are at the bottom of the food chain in nature.
Are Tetras a Hardy Fish?
Yes, tetras are certainly a hardy fish. They can handle quite a bit of abuse and the water parameters can go outside their range and they will be fine.
That said, it does take a little while for them to adjust to a new environment. But if things stay consistent, even outside their range, then they should be perfectly fine.
As I mentioned earlier, a tetra in a healthy environment should live 5 years at an absolute minimum. 10 years is not unheard of even for tetras in a fish tank given the tank is large enough and kept clean.