Common Aquarium Problems

It can be a fun and rewarding experience to bring a piece of the underwater world into your living space. However, there are some common problems that many aquarium owners experience.

From algae growth and ammonia spikes to low water temperature and nitrate buildup, these issues can be detrimental to the health of your tank’s inhabitants. In this article, we’ll explore the causes of these problems and how to avoid them. Read on to learn more!

Common Problems, Prevention & Treatment

It’s important to be aware of the potential problems that can arise in order to keep your fish and other tank inhabitants healthy and happy. Some of the most common issues that aquarium owners face include elements caused by misunderstanding as well as just naturally occurring. 

Here’s a list of common aquarium problems with simple solutions as well as preventive measures I recommend taking:

Algae growth

Algae growth is a common problem in aquariums and can cause an imbalance in an aquatic environment. These algae feed off of nitrates, phosphates, and other nutrients in the water and excessive amounts can lead to poor water quality, fish stress, and a lack of oxygen.

It is important to address algae growth quickly and appropriately in order to maintain a healthy aquarium. 


There are a few solutions to getting rid of algae in aquariums. One is to vacuum the substrate and other decorations to remove excess nutrients.
Algae can also be scrubbed off of the walls and other surfaces with a clean soft brush. If these solutions are not successful, adding algae-eating fish such as otocinclus or common plecos can help control the population. 


Preventing algae growth can be done by controlling the number of nutrients in the water. This is done by performing frequent water changes, controlling the amount of fish food fed, introducing plants for natural nutrient absorption, and using activated carbon or other filtration media to reduce nitrates and phosphates from entering the system.

Additionally, using an ultraviolet sterilizer can help kill any algae spores that enter the aquarium.

Ammonia spikes

Ammonia spikes are a common problem in aquariums caused by an excessive buildup of ammonia (NH3/NH4+). This toxic compound can occur when organic materials, such as fish waste and uneaten food, break down in the water and are not removed by regular aquarium maintenance.

Ammonia can be extremely damaging to the fish and can cause tissue damage, lack of energy, and even death.


The first step to fixing an ammonia spike is to do a water change, which essentially dilutes the concentration of ammonia in the water. If the problem persists, it may be beneficial to increase the amount of filtration, such as adding a filter with a higher capacity or adding additional filtration media.

Additionally, using a product specifically designed to reduce ammonia levels (e.g. Premium Ammonia Remover) can help.


Preventing an ammonia spike can be done through proper aquarium maintenance. Be sure to do regular water changes to remove small amounts of ammonia and other toxins. Make sure your aquarium is not overstocked with fish, as this can lead to excessive amounts of waste being produced.

In addition, remove uneaten food and fish waste from the aquarium on a regular basis. By following these preventive steps, you can avoid an ammonia spike in your aquarium.

pH imbalances

pH imbalance is a common problem with aquariums and is a major factor in fish health and wellness. pH is a measure of acidity or alkalinity that ranges from 0 to 14 on the pH scale. Acid levels less than 7 are considered acidic, levels above 7 are alkaline, and levels at 7 are neutral.

The optimal range of pH for most aquariums is between 6.5 and 8. A pH level that is too high or too low can be hazardous for fish and other organisms in the tank. 


The solutions for pH imbalance vary depending on the severity of the problem. To increase pH, aquarium owners can add a buffer to their aquarium or use a reverse-osmosis filter.

To lower pH, adding peat to the aquarium or lowering the water temperature can be effective solutions. It’s important to test aquarium water often and to make adjustments to pH levels slowly, over the course of several weeks.


To prevent pH imbalance, aquarium owners should avoid overfeeding, as this can cause a buildup of organic waste and rapid changes to pH levels. Performing regular water changes and using an appropriate filtration system can also help maintain stable pH levels.

Regular testing of aquarium water should also be done so that any pH levels that are out of the ideal range can be adjusted quickly.

Low oxygen levels

Low oxygen levels, or hypoxia, are a common problem found in aquariums. Poor aquarium water circulation and too much organic waste buildup are the most common causes of this issue. This can cause fish to become weakened and eventually lead to their death.


Low oxygen levels can be fixed by increasing water aeration. This can be done by installing additional pumps, wave makers, and air stones. Furthermore, the aquarium should be cleaned regularly to remove organic waste and boost oxygen levels. 


Preventing low oxygen levels from occurring can be done by having proper filtration and oxygenation systems in place, making sure the aquarium is not overstocked with fish, conducting regular water changes, and monitoring water temperature. Additionally, the removal of organic waste should be done frequently to prevent its buildup.

Uncycled bacteria levels

Uncycled bacteria levels are one of the most common issues encountered in aquariums. This refers to the bacteria that convert toxic ammonia to nontoxic nitrate. The absence of these bacteria causes ammonia to reach dangerous levels that can be deadly to aquatic life.


If uncycled bacteria levels are too low, then shrimp, aquatic plants, and other aquarium lifers can suffer. In order to fix the problem, a biological filter can be added to the aquarium. This will help regulate the bacterial levels and ammonia concentrations in the aquarium.


To prevent low uncycled bacteria levels, aquarium owners should give time for the aquarium to cycle before adding fish. Adding fish and plants gradually can help build up bacterial levels.

Perform regular water quality checks and keep a close eye on ammonia concentrations to make sure they are in healthy ranges. Adding bacteria supplements can also be beneficial.

Low water temperature

Low water temperature is a common aquarium problem caused by a number of factors such as poor insulation of the tank, cold air temperatures, and too little water movement within an aquarium.

These extreme water temperatures can cause illness and even death in tropical fish and other aquatic creatures. Furthermore, low temperatures result in slowed metabolic processes, lack of appetite, and generally weak health. 


One of the most effective ways to fix low water temperature is to increase the water temperature through the use of an aquarium heater. Aquarium heaters can range from simple designs to more sophisticated options with adjustable settings. Adding insulation to the tank, such as a tank cover, can help keep the water warm.


Preventing the issue of low water temperature can be done by ensuring the tank is placed away from direct sunlight, fans, and cool drafts. You should also consider providing enough water movement, as a consistent current will help keep temperatures steady.

Additionally, being mindful of the nighttime temperature can make all the difference, as cool air at night can cause the tank to cool quickly. Finally, if you keep tropical fish, it is important to select an appropriate heater size for your tank in order to maintain good water quality.

Nitrate and nitrite buildup

The two nitrogen compounds nitrate and nitrite are necessary compounds that can become a problem as they collect. The buildup is a common problem found in aquariums. Nitrate is a byproduct of the nitrification process in a tank and is potentially harmful to fish.

Nitrite is a chemical that is created by the breakdown of ammonia, which is also potentially toxic.


Nitrate and nitrite buildup can be avoided with regular water changes as well as the use of a nitrate filter or media like activated carbon which will help reduce nitrates and nitrites in the aquarium. Providing an aquarium with ample oxygenation and aeration can also help reduce these levels.


To prevent nitrate and nitrite buildup, it is important to maintain appropriate water quality levels, test the water regularly, and not overstock the tank.

Regularly cleaning the aquarium and gravel, as well as having a properly functioning filtration system, can also help maintain optimal water levels. It is important to avoid overfeeding the fish and any other form of excessive organic matter in the aquarium.


Overfeeding is when too much food is added to an aquarium and the fish are unable to consume it all before it decomposes resulting in water quality issues such as ammonia and nitrate spikes.

Nutrients from the food can cause an algae bloom, making the water cloudy and green. It can lead to unhealthy fish and long-term damage to an aquarium’s ecosystem.


Fixing overfeeding can be accomplished by immediately removing any uneaten food from the aquarium. Perform a partial water change, replacing 25-50% of the water with conditioned water. It’s also important to do regular water testing to monitor water quality and take action as needed.


Preventing overfeeding starts by learning how much food your fish eat. Feed only the amount of food the fish can consume in three minutes. It is also important to avoid overstocking the aquarium and feeding a balanced diet to provide all necessary nutrient sources.

Use floating algae wafers and flakes over sinking fish pellets to make sure any uneaten food will float instead of sinking and decomposing in the substrate. Lastly, avoid highly processed foods and feed your fish natural foods.


In conclusion, proper knowledge of common aquarium problems and the right preventative measures can make all the difference in the health and beauty of your tank. Take the time to regularly test the water, stock the tank appropriately, use a suitable filtration system, introduce a variety of plants, and keep the decorations and gravel clean. With these steps, you can keep your aquarium thriving and healthy, both for you and your fish!

Frequently Asked Questions

The short answer is that a fish cannot survive more than a few minutes out of water. The exact amount of time a fish can live outside of water depends on the species, the temperature of the air, and the humidity. Some fish such as eels are able to survive up to an hour in some cases.

There are several steps you can take to keep your fish tank clean without changing the water. Start by cleaning the sides and decorations of the tank with an algae scraper or sponge. If your tank contains plants, you‘ll want to check them regularly for algae and remove any buildup.

You should then perform a partial water change (1025% of the water) every two weeks to remove any debris or buildup in the gravel. Additionally, vacuum the gravel each time you do a water change to remove any debris or waste. Finally, make sure to check the water parameters to maintain an optimum balance and keep your fish healthy.

To make your fish tank water crystal clear, start with a thorough cleaning of the tank. Empty and rinse the tank, decorations, and filter, and change out at least 2550% of the water. Make sure to also clean and/or replace the filter media and gravel as needed. 

Then, use a water conditioner when replacing the water to help reduce chlorine and other toxins. Also, feed your fish only what they can consume in 23 minutes to prevent excess food from decaying and clouding the water. Finally, use a clarifier product to help bring out the clarity of the water.

Yes, you should take your fish out when cleaning the tank. This will keep the fish from being exposed to any chemicals in the cleaning products and ensure that the water stays clean for the fish to live in.

Yes, it is possible to leave your fish tank for 3 weeks. However, it is important to properly prepare the tank for this extended period of inactivity. You should reduce the amount of food you provide to your fish and do a large water change (at least 25%) prior to leaving. 

Additionally, it is recommended to add a water conditioner to keep the levels and conditions of the tank consistent while you‘re away.

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