5 Obstacles To Fish Tank Health (And How To Beat Them)

Article published at: Dec 26, 2023
5 Obstacles To Fish Tank Health (And How To Beat Them) - AQUA VIM
All Blog


Whether you’re a beginner or a seasoned pro, maintaining the right environment in your fish tank can be quite a challenge. Sometimes the tiniest changes can disrupt the aquatic world you have built, and the culprit can be difficult to identify. We’ve identified the biggest challenges to a healthy tank and provided tips on how you can overcome these obstacles, prevent future occurrences, and restore harmony in your fish tank. Here are the top 5.

1. Stress

Bobbing along in the water, not worrying about your next meal doesn’t seem like it would be stressful. However, stress is a major factor in fish health. Like humans, fish have a biological response to stress that can affect their health and make them more susceptible to parasites and infections. Stress can be caused by too few fish, too few places to hide, harassment from other fish, excessive netting, or rearranging the tank ornaments. Anything that causes an uncomfortable environment can create stress in your fish.


Stress in your fish can be hard to identify but keeping a stress free tank doesn’t have to be difficult. Research your fish, so you know if any are likely to be more aggressive fish who may cause issues. Make the tank environment as natural as possible and provide plenty of hiding places for your fish. When introducing new fish to the tank, do it slowly, and acclimate them properly. Reducing stress will leave you with healthier, happier fish.

2. Poor Water Quality

Rookie mistakes in keeping fish are failing to check the water quality before adding fish to an aquarium or adding too many fish before the nitrogen cycle has been properly established. The nitrogen cycle allows good bacteria to build up in the tank to help maintain appropriate nitrogen, nitrate, and ammonia levels. Decorations and gravel that are not specifically designed for fish tanks, can also negatively impact water quality. Gravel or rocks containing limestone can increase the pH of the water and affect fish that require a more alkaline environment.


When you set up your aquarium, allow it to run for 24 hours without adding fish. Slowly add fish, starting with a sturdy species that can handle a range of conditions, this will help kick start the nitrogen cycle and begin introducing beneficial bacteria to the tank. Test the water quality, weekly, this means tracking the pH, nitrogen, nitrates, ammonia level, hardness, and chlorine. Water testing kits are readily available, and easy to use. Only add items to your tank that are approved for aquarium use, to avoid introducing contaminants. Live plants, if carefully sourced can help maintain the water quality in a tank by absorbing excess ammonia.

3. Worms/Parasites

Worms are a common occurrence in fish tanks and aren’t necessarily a sign of anything bad. Non-parasitic worms, such as Detritus worms have no effect on fish, and can in small populations be beneficial.  When worm populations get out of control, however, this can disrupt the balance of the tank environment. Overfeeding, improper cleaning, and failure to properly quarantine new fish and plants can all lead to the rapid spread of worms through the tank. Parasitic worms in fish can be aggravated by stress, poor nutrition, and poor tank conditions. Hookworms, roundworms, flukes, and tapeworms are common parasitic worms found in fish. They can infect the skin, digestive systems, gills, and eyes among other things.


Any experienced fish keeper will tell you, that you can not completely eradicate worms from your fish tank, but you can keep them at manageable levels. Do not overfeed your fish, the excess food can lead to the rapid reproduction of Detritus worms, clean the tank regularly, and carefully clean gravel before transferring it from tank to tank. Always quarantine new fish or live plants before adding them to your tank. You will want to keep them separated for 4 to 6 weeks to make sure they are free of parasites and disease. If you suspect your fish may have an infection due to parasitic worms do not attempt to treat them yourself. Take your fish to a veterinarian experienced in the care of aquatics to confirm the cause of the problem. Attempting to add chemicals that claim to kill worms in our tank, can negatively affect your fish as well. A veterinarian can help you find the correct treatment to keep your fish safe and parasite free.

4. Dropsy

All fish diseases are problematic. Dropsy is common, but what makes it particularly troublesome is that it only attacks immunocompromised fish, and the symptoms can vary wildly. Dropsy is caused by the bacteria Aeromonas. Aeromonas is a common bacteria in fish tanks, but a fish that is suffering from any stress-inducing factor has a weakened immune system and this allows the bacteria a chance to infect the fish. Fish suffering from Dropsy can display a bristly appearance with scales standing out, bulging eyes, swollen anus, a curved spine, loss of appetite, lethargy, pale gills, pale stringy feces, clamped fins, and the classic symptom of a bulging swelling belly. They may display all of these symptoms, or very few, making diagnosis difficult. Further complicating diagnosis is that infected fish may display atypical symptoms such as skin lesions. As the disease progresses it causes the abdomen to fill with fluid as the liver and kidneys fail. Diagnosing and treating at the early stages is necessary for successfully treating this disease.


Noting any abnormal behavior in your fish plays an important role in stopping the spread of any disease. Normal tank maintenance will typically keep stress in your fish low by keeping chemicals properly balanced and reducing the stress of an unbalanced tank. Fish may be suffering from other stressors such as harassment by more aggressive fish, and observation will help you notice if any fish may be at risk of a lowered immune system. Any fish that appear to be behaving oddly should be removed immediately, and placed in a quarantine tank. This will help prevent the disease from spreading to other fish.  The quarantine tank should be treated with one teaspoon of salt per gallon of water in the tank. Combined with a healthy diet this should be enough to treat the Dropsy afflicted fish. Fish further in the disease process should be treated with an antibiotic. 

5. Aggressive Fish

It’s natural for fish to establish a pecking order, particularly when new fish are introduced into an aquarium. Aggressive behavior is also typical of certain species, however, aggression can go on long after a hierarchy has been established and species that are generally passive may suddenly turn into fin nippers. Establishing the cause of the aggressive behavior is important in maintaining the health of the entire tank. As we have mentioned, stress is a common factor in many health problems affecting fish, and bullies and aggressive behavior will increase the stress levels of the fish in the tank lowering their immune systems and making them more susceptible to opportunistic infections such as Dropsy.


Determining the root cause and getting control of the aggressive behavior is the only way to solve this problem before it becomes detrimental to all fish in the tank. If you are aware that the fish causing the problems are not typically aggressive there are several factors to consider. Are they protecting territory? Over time fish may become territorial over certain areas in the tank. Are they a shoaling species? If shoaling fish start turning aggressive it may be a sign that there aren’t enough of them in the tank, and they may be showing aggression in attempts to “socialize”. Is it time to increase your tank size? Even slight overcrowding will cause some fish to start behaving aggressively. Rearranging the tank to prevent territorial disputes can stop some spats. Providing shoaling fish with enough members of their species that they do not become aggressive, 3-4 generally, but not so many that the tank becomes overcrowded. 

Maintaining a fish tank can seem overwhelming and full of challenges. As with anything, basic, preventative care will cut down on the challenges you may encounter. Following these tips to stop problems before they start will make it seem less like an insurmountable task, and more like a labor of love.