Why Is My Fish Swimming At The Top Of My Reef Tank?
If your fish is swimming at the top of your reef tank, it can be one of the most alarming behaviors you may encounter, especially if you’re a newbie reefer. As a passionate reef tank enthusiast, seeing your fish or corals in distress can cause concern. While this may seem like a minor issue, it is often a key sign that something inside your reef tank is not quite right.
Why Do Fish Swim At the Surface?
A fish swimming at the surface of a reef tank is not part of their normal swimming routine - as they cannot talk to you, this abnormal swimming behavior is usually a cry for help. So, if your fish is swimming at the top of the tank, it is your fish’s way of sending an SOS signal, telling you that there is a potential problem that could affect their health and the rest of the aquarium system.
Oxygen Deficiency
The most common reason for surface swimming in saltwater aquariums is low oxygen. The surface of the water in an aquarium has a greater oxygen concentration, which is why they swim there in low oxygen conditions. When they swim to the surface they are just trying to breathe more effectively.
Oxygen can become depleted in a reef tank from various factors:
- Overcrowding
- Insufficient water movement
- High temperatures
- Excessive organic waste
Water Quality Issues
If you have water quality issues this can trigger fish to surface swim. Water parameters such as nitrate, nitrite, and ammonia can quickly cause a toxic environment in closed ecosystems like your reef tank.
When these water parameters fluctuate, fish can experience elevated physiological stress - their abnormal surface swimming behavior is a desperate attempt to escape from the poor water conditions and find an area where there may be better environmental conditions.
Temperature Changes
If you are an experienced aquarium hobbyist, you will be aware how crucial it is to maintain proper temperature levels in a reef tank. If your aquarium is experiencing sudden changes or consistently high temperatures, this may be why your fish is at the surface gasping for air.
To add to that, elevated temperatures in aquariums cause depletions in dissolved oxygen (DO) levels, which force your fish to swim to the surface to seek oxygen-rich areas in the water. Also, increased water temperatures can lead to metabolic changes that make your fish feel less comfortable in their normal zones in the tank.
Diseases & Parasites
If your fish are swimming at the surface yet you have pristine water conditions, then your fish may have an underlying health condition. Some aquarium fish diseases and aquatic parasitic infections can lead to neurological or respiratory issues in fish, altering their swimming patterns. Often, such parasites and diseases are very difficult to detect (particularly microscopic parasites), some even leaving your fish fighting an invisible battle.
Examples that cause behavioral changes include:
- Velvet disease
- Ich
- Gill parasites
Troubleshooting & Managing Surface Swimming
Maintaining Optimal Water Conditions
The first step when noticing your fish swimming at the surface is to check the water parameters and conditions including ammonia, pH, oxygen, salinity, temperature, nitrate, and nitrite. We recommend using a reliable and accurate water test kit with high-quality probes, such as:
- HYDROS Slim Temperature Sensor Probe
- Neptune Temperature Probe
- Neptune Conductivity Probe
- Neptune Double Junction pH Probe
- MA911B/2 pH Electrode Probe
- HYDROS Lab Grade Salinity/Conductivity Probe Kit
These modern test kits/probes offer accurate and fast readings that are valuable to giving you insights into possible issues in your aquarium system.
Increasing Oxygen
If your tank is suffering from oxygen deficiency, do not worry as there are a few ways to boost oxygen levels in an aquarium. At Reefco Aquariums we swear by the use of powerheads and circulation pumps, especially in systems that have higher stock inside.
We suggest the following for maintaining good water movement in an aquarium:
- Nero Powerhead
- VorTech MP40mQD
- Orbit 4 Cross-Flow Pump - great for mimicking ocean movements
In addition to the above, you can also install an air stone or upgrade your current protein skimmer to boost oxygen exchange in the water.
If your oxygen levels are extremely low, and you do not have any special equipment to hand, then emergency protocols can be followed:
- Pouring water into the aquarium from a height
- Manually stirring the water, taking care not to injure any aquatic life
- Perform large water changes
Addressing Water Conditions
Restoring the water quality inside your aquarium involves a few steps:
- Use high-quality, conditioned saltwater when performing partial water changes
- Remember to clean the protein skimmer
- Check & replace the filter media
- Check your biological and mechanical filtration systems are functioning properly
Managing Temperature
We highly recommend investing in a high-quality thermometer/temperature probe. For reef tanks, maintain a temperature between 76°F-82°F, however, always check the temperature news for your fish and corals.
Aquarium placement can also play a role in managing temperature levels. You should avoid placing your aquarium close to any windows, heaters, AC units/fans, or other areas that could cause temperature fluctuations.
How to Prevent Fish Swimming at the Tank Surface?
At Reefco Aquariums, we follow one of the biggest sayings in the hobby when it comes to preventing issues, and that is prevention is always better than a cure.
You maintenance routine should include the following:
- Regularly cleaning and maintaining aquarium equipment
- Performing water changes every other week
- Testing the water parameters every week - the Neptune Trident Water Analyzer is a game-changer
- Daily inspections of fish and coral health, looking for abnormal behaviors and signs of common fish and coral diseases
- When adding new corals or fish, always quarantine* them and control how many fish you add at one time. It is essential to quarantine fish and corals before introducing them into your tank. This can be done using a separate tank, called a quarantine tank. This will allow you to observe the fish for potential health issues, and acclimate them so they will not suffer from shock during the move into their new home.
When to Ask for Help?
If your fish continue to surface swim despite trying everything in this article, do not hesitate to contact an experienced reef tank/fish specialist or fish/marine vet. Some issues need help beyond our control, plus these specialists can perform targeted treatments that go beyond standard hobbyist capabilities.
Conclusion
If your fish are swimming to the surface, it is likely that something is not quite right inside the aquarium. The key to preventing fish from swimming to the top of the reef tank is creating a balanced marine system and carefully monitoring fish behavior and water quality.
If you need any advice from our specialist team, do not hesitate to contact us here at Reefco Aquariums - where we are always happy to help you on your aquatic journey.
