Betta Stress

How to Tell if a Betta is Stressed, and Can a Betta Die from Stress?

Stress is a major issue in aquariums. While it is easy to avoid and prevent, accidents happen, and these accidents can have severe unintended consequences. It is good to know the impact of stress and how to fix the issues it causes.

Stress can kill fish, though it often does not kill bettas outright. Bettas are one of the hardiest fish, so while stress may not be the final factor in their deaths, it can start a chain of events that will kill them. Most of the things that will stress out betta are severe enough that they can be easily identified.

In this article, we will discuss signs of stress, the impact of stress, diseases caused by stress, dropsy, potential stressors, and reducing stress.

Signs of Stress

The biggest sign of stress in bettas is dull coloration. If your vibrant little buddy has become a duller color, there is a major issue, and you need to figure out what is going on. A huge warning sign is one or more horizontal stripes going down the middle of your fish.

This is called a stress stripe and it only appears after repeated, severe stress. If you are seeing a stress stripe (not to be confused with vertical, thick, breeding stripes), there is something very wrong with your betta’s home.

Other signs of minor stress include hiding frequently, refusing food, lethargy, and a betta that startles easily. All of these signs are very common when introducing a new betta to its permanent home, as the move does cause stress. If these symptoms do not go away in 3-5 days, there is something else wrong with the betta.

All of these symptoms are also early indicators of disease, so it is important to observe your fish closely once it shows even one of these signs.

Impact of Stress

The most concerning impact of stress is a weakened immune system. In the wild, fish with weakened immune systems do not live long and often infect others around them. This is especially important to keep in mind if your betta is in a community tank.

Fish often get sick during shipping or at fish stores due to the contact with other carriers and simple stress. When you have an established tank with fish who have not been in contact with diseases for months, they can still get sick from stress.

In our water, even treated tap water, there are some bacterium, fungus, and other pathogens that can infect fish. Pathogens cannot infect healthy fish with functioning immune systems, but once your fish is hurt or stressed, expect illness, especially bacterial infections.

If the stress is caused by an injury, such as a fish hurting themselves on a decoration, you need to do extra water changes to prevent illnesses. The fungus can only affect flesh that is dead or dying, so keep an eye on that injury. On the flip side, if you see a fungus looking fluff on a fish that did not have an injury, it is bacterial, and possibly columnaris.


The most common diseases caused by stress are external and internal bacterial infections. These can be both gram negative and gram positive, so it is best to have a medication that will treat both strains.

External bacterial infections are generally easy to identify, despite the wide range of symptoms. They can appear both raised and sunken, and red, gray, black, or white. The ones most commonly seen are red sores on the fish.

If the infection site becomes ringed with gray or black, this is a very bad sign. This often means the flesh around the infection site has begun to decay, which means more pathogens can latch on and that you are dealing with a particularly virulent strain of infection.

Even though this was caused by simple stress, fish often cannot fight these infections off by themselves and require medication.

Internal bacterial infections can be much harder to spot and often go unnoticed. This is because there are often not any external bacterial signs, and it is often impossible to diagnose the issue based off behavior alone.

Some internal bacterial infections do have external signs, such as septicimia, pop-eye, and dropsy, the latter of which we will discuss in detail. Septicimia can often be seen are red lines under the skin and in the fins and can be fatal if not treated.

Pop-eye is not often a lethal issue, but a fish can lose the affected eye if it is not treated. Pop-eye looks like it sounds; the eye bulges outwards from the head.

Some good medications for these issues include macaryn 2, furan 2, kanaplex, and erythromycin. Some of these will kill your beneficial bacteria, so you will have to recycle the tank, but it is better than losing your buddy.


Dropsy is unfortunately a relatively common affliction that has four different main causes. The most common cause is an internal bacterial infection of the kidney.

Dropsy is nearly synonymous with kidney failure, as it is a symptom of kidney failure. This condition is difficult to treat, as you first have to fix the ailing kidney, but Dropsy itself can also be lethal and moves quickly.

Dropsy is identified by the swelling of fish and pine coning of scales outwards. From the top, you will see all the scales sticking out to the side.

A fish’s kidney not only cleans the blood, but also regulates fluids in and out of the body. Once the kidney fails, fluid begins to build up and force the fish to swell. In fact, the scales sticking out are not due to the body swelling, but due to the actual scales swelling.

This is often a fatal disease, but I have been able to successfully treat it twice. One fish relapsed but is still alive. In fact, the first fish that had Dropsy developed an internal bacterial infection due to the stress of moving to a new tank.

The first step is to keep kanaplex on hand. The progression of Dropsy is so fast that a fish will die in 2-7 days and will be past the point of treatment after 1-3 days, so waiting on shipping is not an option.

As soon as you see scales pine coning (they will begin pine coning right behind the gills a day or two after the eyes swell slightly), dose kanaplex. Next, add 1tbsp per 5 gallons of unscented Epsom salt into the tank to reduce bloating. The kanaplex dosage lasts for 6 days, and you need to keep the Epsom salt in the tank for this time period.

Potential Stressors

The five biggest stressors to bettas are bad parameters, a lack of decorations, tank mates, seeing their reflections, and temperature fluctuations. Even just one of these can have a serious impact on a betta and lead to their death.

Bad parameters or poor water quality often refers to ammonia, nitrite, and nitrate. These are the main compounds of the nitrogen cycle, which is something every fish keeper needs to be aware of if they want to keep their fish alive.

If there is any amount of ammonia or nitrite, your fish is being poisoned and will be stressed. Even 0.25 ppm is toxic to bettas and can be lethal overtime. Aside from the direct impact of being poisoned, it is also very stressful, which can lead to the fish succumbing to both the poisoning and a secondary infection.

Nitrates are safe up to 20ppm, but higher levels cause stress and a diminished immune system over time. If your fish seems stressed but you have 0 ammonia, 0 nitrite, and less than 20 nitrates, you can look elsewhere.

A lack of decorations causes severe stress in bettas. While they are a carnivore, they are also a prey fish and have a strong natural instinct to hide. If they cannot hide, they will be constantly stressed.

Betta splendens is a territorial fish, so seeing their reflection or having tank mates can stress them to death. They will constantly try to get rid of the intruder(s) in their space, and if they cannot, they will become stressed and lash out. However, not all bettas are overly aggressive, and some get along with other fish wonderfully.

Their temperature needs to be between 78-82 degrees, but if it fluctuates more than 2 degrees per hour, you fish will be stressed.

Reducing Stress

The best way to reduce stress is to get rid of the stressor. If bad water quality is stressing your betta, you need to do as many water changes as it takes to get rid of any ammonia or nitrite and to lower nitrates to a safe level.

If your fish’s reflection is causing stress, add a cover to the outside of the tank or reposition the light until it can no longer see itself. On the other hand, if the issue is tank mates, you need to move your fish to a solitary tank.

Adding decorations is easy enough, you just need to make sure that the decorations are not sharp. For reference, run a tissue over the decoration; if the tissue tears, your betta’s fins will tear.

Finally, if your temperature fluctuates, you either need to buy a heater if you do not have one or buy a new one. Since this much fluctuation is abnormal, you can probably return and exchange the heater at no cost.

In conclusion, stress has a major negative impact on the health of a betta fish. It can cause several different ailments, normally a bacterial infection of some kind. Bettas have some major stressors, but you can easily remedy them once they are identified.

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