One of the commonest reasons is that the fish might be in stress due to improper tank conditions or diseases.
The stress can also arise due to harassment by other tankmates. The pregnant females are more prone to the condition.
It is important you understand the main causes so that you can take the right measures immediately. Swordtails are peaceful and beautiful species in addition to being active and social.
If your swordtail fish is constantly staying and swimming at the top of your aquarium, that should be alarming because it might be unwell. This can be caused by stressed, illness, low oxygen level, poor water quality or maybe pregnancy.
Therefore, finding the solution to this problem is important. Here are some of the reasons your fish might be swimming on the surface.
Stressed Swordtail Fish
Each time you look into your aquarium tank you might wonder how a peaceful life feels like. After all, your fish will be swimming around the beautiful tank throughout the day, but you will have to feed and care for them properly.
This might sound odd, but your swordtails may be stressed – more like some things stress people. The sources of stress in people are mostly related to general business, relationships and the home condition.
For swordtails, aggressive tank mates, bad water conditions and the surrounding environment can cause stress. In humans, stress causes serious health complication and the same apply to fish.
The stress can even kill them. Therefore, if you find your swordtail swimming at the top of your aquarium tank or bottom or staying in isolation, you should work to manage that stress.
Aggressive Tank Mates or Poor Water Quality
The water quality is important for the survival of your swordtails. Both nitrite and ammonia affect the grills of swordtails and they can cause gasping. So, you will have to test the levels of the two elements in your aquarium tank before the problem worsens.
Any sign of nitrites or ammonia should be terrifying. To solve the issue, you should do at least 50% water change by topping up with dechlorinated tap water.
The presence of ammonia and nitrites can be cause by un-cycled aquarium, inadequate biological filter media, overcrowded tank or undersized filter.
Dissolved gases might be another reason your swordtails are swimming at the water surface. A lot of carbon dioxide (CO2) in the water means that the amount of oxygen is less.
If your tank is planted and you have been dosing CO2, you will have to ensure that you are not adding a lot of it. If the CO2 unit malfunctions and releases too much of it, you will have to boost the aeration so that you maintain the right levels.
If the tank is planted and you find the fish swimming at the surface, then the algae and plants depleted the oxygen at night and the CO2 levels increased. To solve that, you just need to boost the oxygen levels at night.
Lastly, the swordtail might choose to remain at the top so that it can remain safe from the aggressive bullies. The pregnant fish are usually more sensitive than the others are and it is always good you transfer them to a breeding tank.
If you have already stocked the tank with many males, shift some of them to a different tank because they are known to harass the females. That is more likely when the number of females is less.
Swordtail Fish Floating at the Water Surface
If the fish floats on the surface or is unable to rise from the bottom, then it has a buoyancy problem. Buoyancy problem is more common and a recent study that the Japan Aquaculture Society Journal published named the condition tenpuku disease – meaning capsized.
The disease result from starvation, systematic diseases (parasitic, viral bacterial or cancer) general weakness, broken fins, eroded fins excessive air in the abdominal cavity or gastrointestinal tract or swim bladder disease. A veterinarian will provide you with the right cure.
High Water Temperature and Low Oxygen Level
The swordtail might remain at the water surface because it contains a higher amount of dissolved oxygen. So, if they cannot get enough of it inside the water, they will swim to the highest point and gasp.
The gasping might also be a result of some other factors in the water. If the water gets warmer, the level of oxygen in it will reduce. Remember to monitor the temperature and maintain it at a level between 24 – 28 °C (75 – 82 °F).
If the weather is hot, your tank might be heating naturally, which means that you will have to cool it down and boost the aeration. Do not blame the temperature each time you see the swordtails swimming at the surface because that might be a result of a disease of pollution.
A malfunctioning heater might remain at the “on” position and cause overheating of the water. Swimming of swordtails on the surface is a good sign that something is definitely wrong. Therefore, if the water is hot or very warm and the heater light has remained on, the heating system might be the cause.
You will have to replace it. A malfunctioning heater will cause the temperatures to rise to over 30 degrees Celsius or 86 degrees F. Most heaters in the market are reliable, but the results can be devastating if they go wrong.
Sick Swordtail Fish Stays at the Top
Some disease that affects gills can cause gasping. Look for any signs of infection like clamped fins, spots and secondary infections like bacterial or fungus diseases.
Most of them attack the gill tissues, which either cause the production of excess mucus or damage the tissues, therefore, reducing the amount of oxygen your swordtails can extract from the water. Gill diseases are tricky and it is hard to diagnose them.
Therefore, if everything else seems right but you suspect a gill disease, you will have to consult a specialist dealer or an experienced fish vet.
Swim bladder malfunction is among the commonest diseases in swordtails. It happens when the organs swell and lead to suffocation of the swim bladder.
You can get the treatment for this condition in any pet store. Add the medication to the water and the fish will start getting better with time.
Female Swordtail is Ready to Give Birth
Pregnancy might also cause the swordtail to start swimming at the top of the tank. During labor, swordtails tend to restrict movement and lie in solitude. In fact, that is their only parenting instinct.
But if the swordtail is gasping for air at the surface, then there are chances of nitrites or ammonia poisoning. Measure the concentration of toxic nitrogen compounds and ensure that both nitrite and ammonia are at the zero concentration level. The nitrate level should be below 40 ppm, ammonia and nitrites should be 0 ppm.
If ammonia and nitrites are above the recommended level, you will have to start by changing the water by at least 50% of the water volume.
If any of your swordtails is pregnant, you will have to pay attention to its behavior. If you keep it alone, it will get stressed.
They will be more sensitive to changes during pregnancy, which means that it is good you leave it in the same tank and allow it to do its thing. The fish will give birth without any assistance.
Keep in mind that pregnancy nature will make the swordfish prone to bullying.
If the fish is floating at the top or bottom of your aquarium tank, remaining inactive, hiding behind the plants, there is a better chance that she is in need of privacy. Shift her to a breeding box and leave it until she drop all fry.
Are my Swordtail Fish Happy?
A happy swordtail will swim actively in the whole tank and will not float at the top of your aquarium tank, lay at the bottom or hide behind the ornaments and plants.
The fish will also eat regularly and swim very fast at the surface during the feeding time. Happy fish should not have blemishes or white spots on the body. The fins should not be ragged or a ton and the eyes should not bulge.
The swordtail might expand its grills regularly to take in more water and oxygen. The scales should be brightly colored.
How to Treat Sick Swordtail Fish?
To treat the fish, you will have to start by checking the aquarium water. Poor quality water causes around 90% of all fish diseases. Unsuitable water causes stress and environmental diseases, which may appear to be bacterial or parasitic diseases.
Poor water quality may also suppress the immune system of your swordtails, therefore, reducing their ability to fight diseases. Ensure that all the water parameters are correct to rule out the main issues.
And because prevention is better than cure, you will have to quarantine any new swordtail, check the health of a fish before buying, maintain the water quality and avoid acute exposure to nitrite, ammonia and nitrate.
Ensure that the temperatures and PH are consistent. Practice good nutrition by providing various nutrients. To help the sick fish:
- Provide them with aquarium salt, which is known to soothe symptoms
- Adjust the temperature – by raising the temperature slightly, you will be able to kill most of the external parasites
- Buy the right medications from the local store
- Act early to prevent the spread to other swordtails
- Clean up the aquarium tank before you start the treatment and
- Remove carbon before administering the medication because it can remove it from water
What Should I do With Pregnant Swordtail Fish?
The pregnant swordtails do not exhibit mood swings, but they require good water conditions for better health. When a swordtail is closer to giving birth, you will have to separate it from the others by taking it into a different tank.
There, it will deliver its fry smoothly. The male swordtails are a big threat to pregnant females, particularly because they get aggressive toward the females and that alone can stress them.
Also, avoid keeping the pregnant swordtails in breeding traps because they are congested and they will not provide your fish with enough room for swimming.
That might also create other problems for the pregnant swordtails that might lead to earlier birth of fries or even abortion.
A swordtail that is ready to give birth will stop eating and stop swimming or slow down. It might also stay in one position or sink to the bottom and remain there for a long time.
After the swordtail gives birth, move it to it to the community tank to eliminate the chances of eating the fry.