What Kills Fish In Aquaponics?

What kills fish in aquaponics?

Poor Water Quality

Poor water quality is the leading cause of fish death in aquaponic systems. Water parameters such as temperature, dissolved oxygen, pH, and ammonia levels can have a major impact on the health of your fish. It is important to monitor these parameters and make adjustments as needed to ensure the water stays within a healthy range for your fish.

In this article, we will discuss the details of water quality and how it can affect your fish in an aquaponic system.

High Ammonia Levels

High levels of ammonia (NH3) in aquaponic systems can be extremely detrimental for fish and other aquatic life. Ammonia is naturally produced in large amounts from fish gills, urine and feces and can accumulate to high toxic levels if not managed correctly. Ammonia is also introduced through organic matter decomposing from uneaten food scraps and plant debris.

An aquarium with high concentrations of ammonia will lead to a build-up of toxic metabolites that rapidly diminish the health of fish and other water inhabitants. Aquatic organisms are especially vulnerable to these conditions due to their hypersensitive gills that sensitively detect an increase in ammonia levels. Too much ammonia can cause serious damage, reducing coloration, stunting growth and even causing death amongst aquatic species.

To mitigate against high ammonia levels, aquarists need to invest time into monitoring their aquarium water parameters, checking water pH, nitrogen cycle balance and temperature regularly with a reliable test kit or electronic monitor. To ensure the best outcome it’s important to perform frequent partial water changes over time to remove accumulated pollutants from the system. Adding specialized filtering media will also reduce concentrations of free-swimming proteins like ammonia in the tank’s environment by:

  • Selectively removing harmful pollutants present in tap water
  • Photodegrading them using biomass fouling control features such as biocapacitive elements or ion exchange resins
  • Trapping them inside the cell wall matrix removing them from solution chemistry
  • Freeing up bio-available ions that make up ammonias molecules found within your aquarium’s water column

This will prevent fish off gassing outside dangerous or deadly toxicity levels, leaving them with perfect living conditions so they may enjoy their living environment as close you ever possible get it – clean, clear, healthy! Just give us a call today!

Low Oxygen Levels

Fish require oxygen to survive, and purifying water is important in aquaponics systems. Poor water quality manifests in a number of ways, but low oxygen levels can be especially devastating for fish. It is difficult to keep high levels of oxygen in tanks because bacterial respiration uses up the majority of it. If oxygen levels become too low, fish can experience what’s called ‘suffocation’ – they aren’t getting enough O2 and therefore cannot get enough energy to power their muscles and organs necessary for life. Fish suffocating from low oxygen levels will become listless and not respond to food or motion, as well as bubb

High Temperature

High temperature is one of the major causes of poor water quality in aquaponics systems. When water temperatures are too high, fish become stressed and may suffer from health problems such as gill damage, severe suffocation, or even death. High temperatures also encourage the growth of disease-causing bacteria and parasites which can lead to significant losses in production.

Fish require a constant supply of oxygen to survive, so increasing water temperature affects the solubility and availability of dissolved oxygen (DO) in the water. As it becomes more difficult for fish to take up DO through their gills when temperatures increase, they become increasingly stressed and will eventually die if not cooled down quickly enough.

Lowering the water temperature by increasing aeration results in increased DO levels, which relieves fish stress and allows them to function properly again.

Air conditioners, ice packs, or misting fans can all help lower water temperature in aquaponics tanks if regular aeration fails to provide sufficient relief from high temperatures. Additionally, proper stocking density is important for avoiding high-temperature issues; overcrowding leads to an increase in metabolic activity throughout the tank which further raises already-high temperatures and increases stress on fish even more.


Fish are susceptible to many different kinds of disease, which can cause death in aquaponic systems. Common culprits include parasites and bacterial infections, but there can be other factors at play as well.

In this article, we will discuss the most common diseases and how to protect your fish from them:

Bacterial Diseases

Bacteria are one of the major causes of fish death in aquaponics systems. It is important to understand the different types of bacterial infections, as well as the signs that indicate an infection is present, because prompt treatment can often save fish lives.

Common bacterial diseases include Columnaris (also known as Cottony Bacterial Bloom), Aeromonas, Furunculous, Monodon and Vibrio. Columnaris typically appears as a white-gray growth on the body and fins of fish. Fish infected with Columnaris often display stress symptoms such as rapid breathing and darkening of color. To treat this infection you will need to adjust water parameters (pH, temperature) and provide antibiotics or a bio-security treatment like formalin baths or injection with oxytetracycline.

Aeromonas bacteria can cause ulcerative lesions on your fish and often starts with a red “blood” streak between their dorsal fin and tail fin before manifesting into white open lesions with bright red edges. Treatment for Aeromonas begins with improving water quality including pH levels, addition of beneficial bacteria to stabilize the bio filter system, plus treatment options such as antibiotics or activated carbon baths.

Furunculosis also appears first as small red streaks on fins before developing into deep ulcerations in gills and fins of affected fish. Bacterial treatments are generally used to treat Furunculosis successfully but it needs to be combined with improved water values for pH levels, dissolved oxygen content and temperature levels too.

Monodon and Vibrio are serious infections that can either cause white spots similar to “ICH” or a sandy brown slime coating that is produced by bacterial growth under protection from scales or skin flaps which will eventually cause organ failure if left untreated too long due to its systemic nature within other organs such as gills or heart tissue. Treatment includes keeping sanitary conditions within your system plus use antibiotics through medicated food or injections when necessary combined with improved water parameters too (dissolved oxygen content/ temperature).

Parasitic Diseases

Aquaponic systems rely on the healthy balance of organic aquatic life to be successful. Unfortunately, parasites can enter into the system and cause a variety of diseases, making it necessary to recognize the signs of infection and how to prevent it from occurring in the first place.

Parasites are versatile organisms that can come in many forms such as protozoans, nematodes, fungi, ciliates, flukes, leeches and worms. They are very common in aquaponic systems due to their use of organic material as a food source which lives principally in fish waste products or uneaten food that begins to accumulate on the bottom of your tank environment.

Common parasitic diseases include Ichthyophthiriusmultifiliis (commonly known as Ich or Ick), Costia necatrix (Costia), Trichodina pediculata (Trichodinids), and Epistylis spp (Epistylids). These parasites can lead to damage on skin and fins of fish if left untreated. Some signs that your fish is infected include:

  • loss of appetite or appetite suppression;
  • panting at water’s surface for oxygen;
  • white spots on skin or fins;
  • excess mucous production;
  • torn fins;
  • unusual behaviors such as swimming erratically or rubbing itself against surfaces;
  • cloudy eyes caused by bacterial infections due to damage caused by parasites.

If left untreated these parasites can lead to death in certain types of fish. To avoid them it is important to keep your water clean, oxygenated and well circulated with filters checked regularly for maintenance purposes so that any toxins are quickly removed from the environment before they become a problem.

Fungal Diseases

What kills fish in aquaponics?

Fungal diseases are the biggest threat to any aquaponics system. Fish become infected with certain types of fungus from poor water conditions such as an ideal environment for excessive nitrate accumulation, improper pH fluctuations, and not enough oxygen. Symptoms to identify include slimy patches on the fish’s body, loss of appetite, lethargic behavior, labored breathing, fraying or darkening of fins and scales. If left untreated, the fish will eventually die within a few days.

Fungal diseases can often be treated with an effective anti-fungal medication available from your local aquarium shop or hobby shop. Before starting medication be sure to read up on both proper dosage and tank compatibility information provided by the manufacturer in order to properly administer the remedy correctly and avoiding any potential side effects from poor treatment administration. Additionally fungal infections are airborne so you may need to treat the water and tank surfaces separately in order to fully eradicate the fungus from the environment altogether.

Poor Nutrition

Poor nutrition is one of the leading causes of fish death in aquaponics systems. The fish feed you purchase may not provide the proper nutrients for your fish, leading to a deficiency in their diet. In addition, your fish may not be getting enough oxygen or other essential elements if the water conditions are poor. Understanding the nutritional needs of your fish is key to keeping them healthy. Let’s explore this further.

Insufficient Macronutrients

Aquaponic farming is an intensive practice and depends upon fish health to ensure that the farm environment remains in balance. Poor nutrition due to insufficient macronutrients, micronutrients, vitamins, and minerals can cause a range of afflictions including diseases, weakening of the immune system, stunted growth or death.

Macronutrients are classified into three groups: carbohydrates, lipids and proteins. Fish require all three for proper health and maintenance. Major deficiencies in any of these components lead to poor health or even death of fish in an aquaponic system. Insufficient amounts of carbohydrates (sugars) can cause metabolic disorders as well as reduced spawning activities from adult fish; lipids (fats) are necessary for energy metabolism as well as cell maintenance but insufficient amounts can cause declining illness episodes; and proteins are key elements for growth control and reproduction that when low leads to debilitated parenting behavior from adult fish. Additionally, a lack of micronutrients such as calcium, magnesium and iron can also lead to serious deficiencies that must be corrected with supplementation or selection of food sources rich in these trace minerals.

It is important to regularly monitor the diet of your fish to ensure they receive the right amount of macronutrients, vitamins and minerals needed for optimal health throughout their life cycle in aquaponics farming environments.

Insufficient Micronutrients

Poor nutrition can result from an inadequate intake of both macro- and micronutrients. While most people have probably heard of macro-nutrients like carbohydrates, proteins and lipids (fats), they may not be familiar with the term micronutrients, which refers to vitamins and minerals necessary for proper growth and development. Deficiencies in either group can have serious consequences for one’s health.

Micronutrient deficiencies occur when there is an inadequate intake of either vitamins or minerals. This can result from eating a poor diet that is low in essential nutrient-rich foods such as fruits and vegetables, or due to illnesses that effect the way food is absorbed by the body. Common micronutrient deficiencies include lack of Vitamin A, iron deficiency anemia, iodine deficiency disorders and lack of zinc.

Without enough essential micronutrients such as Vitamin A, vitamin E, Vitamin B12 and folic acid, individuals may experience growth retardation or weakened immunity. Furthermore, certain types of cancers can develop due to low intake levels of certain vitamins or minerals such as these nutrients that are important for cell division or replication processes in the body. Individuals who are unable to access food because of poverty or political unrest are particularly vulnerable to experiencing extreme forms of malnutrition if intervention is not provided in some form.

Poor Quality Feeds

Fish require a balanced diet to remain healthy, and their diets will differ depending on the species. Poor quality feeds may lead to lower growth rates, increased mortality, disease issues and poor water quality. For example, high phosphorus/protein levels in feed can contribute to eutrophication in the system (a process which releases toxins into the water leading to fish death).

It is vital that you choose your feed wisely, as it will often make up the single largest cost of raising fish in aquaponics systems. It’s best to buy them from approved vendors who have built trust with fish farmers over time and know the quality of their product. If you don’t have access to professional-grade feed, try looking for natural sources such as worms or insects as a source of sustenance for your fish.

It is also important to ensure that your feed is made mostly out of plants – not animal byproducts or GMO ingredients – as these tend to be higher in phosphorus/protein levels (and cost more). Avoid using generic commercial fish food with artificial dyes or flavors. These can not only be harmful when they enter into our water systems but they are also costly over long periods of time due large waste created by uneaten feed.


Predation is one of the most common causes of fish loss in aquaponics. Predators like birds, snakes and rodents can easily find their way into a system and decimate a population in a very short amount of time. Additionally, some aquatic species, such as turtles or large fish, can grow large enough to become predators themselves and endanger the safety of smaller fish.

In this section, we’ll discuss the different types of predators and how to handle them:

Predators in the Aquaponic System

The aquatic environment of an aquaponic system is not isolated from the outside world, and at some point, predators will likely enter the equation. A few different types of predators can attack fish in an aquaponic system, but their presence is preventable. Knowing how and why they are attracted to our systems is key to avoiding a predatory disaster.

Mammalian Predators The most common type of mammal that preys on fish in an aquaponic system is the cats and dogs many people keep as pets. Though it’s easy to underestimate the threat posed by these beloved companions, cats and dogs take great pleasure in pouncing on small creatures every chance they get, particularly if those animals move around quickly. If possible, keep these furry friends away from where your fish are housed or make sure their attention isn’t drawn towards them.

Aquatic Insects Insects like dragonfly larvae will also prey on fish in the system if food sources are scarce. These aquatic insects lay their eggs near protected areas where there’s plenty of food, such as grasses around your pond or water surfaces near tilted grow beds. Keep your water clean to help reduce insect activity near your system by removing any diseased or dead vegetation that adults may lay eggs in or around.

Fish-Eating Fish Another type of predator may come from within – other species of fish! Predatory fish like bass and trout feast on smaller varieties such as tilapia and goldfish; when introducing new species into your tank you need to evaluate possible mismatches between smaller and larger fish so that everyone can coexist peacefully in harmony with each other without fears about survival rates decreasing due to predation problems.

Predators from the Outside

Fish in aquaponics systems are not immune to predators from the outside. These predators can be birds, large fish, and even humans.

  • Birds of prey can swoop down and catch fish in the water.
  • Large fish, such as bass or northern pike, have been known to take small fingerlings from growers’ systems. In some cases these predator fish have even been invited into the system deliberately by advanced growers who hoped to harvest them later.
  • Finally, some unscrupulous people might try to steal or harm your fish. It is important to provide adequate security for sensitive aquaponic systems. Motion detectors, security cameras, or-in extreme cases-guards on site might be necessary to protect your investments.

In any case, it is always a good idea to review your aquaponic setup regularly and take steps if needed to reinforce protections against potential predators.

Poorly Secured Tanks

Poorly secured tanks or aquariums can be an open invitation for a variety of predators. Though smaller fish are usually safe from mammals like hawks and cats, they are vulnerable to other land-based creatures. Rodents are attracted to aquaponics tanks due to the abundance of food sources present. Rats, wild mice, and snakes can make their way into the tank and begin preying on fish. Small lizards can also gain access to unsecured tanks, though they typically focus more on insects than the fish themselves.

It is important to ensure that all outdoor aquaponic systems are properly secured against any potential predatory intruders such as birds and cryptozoans alike. To do so, tanks should be:

  • Covered at least partially with fine mesh or opaque tarp that cannot easily be pierced by claws or rodent teeth.
  • Sealed along edges that would prevent large animals from entering the system from below.
  • Have a guard around the tank itself to further safeguard its inhabitants from land-based predators.


Fish in aquaponics systems are susceptible to stress due to a variety of factors. Poor water quality, changes in pH, and overcrowding are all potential sources of stress that could lead to the death of fish in a system.

To prevent fish health problems, it is important to understand how stress affects fish and how to reduce it. Let’s look into this further.

Unfavorable Conditions

In addition to the toxicity levels of certain compounds and the presence of mobile organisms, unfavorable environmental conditions can create a stressful situation for your fish in an aquaponic system. Stress can significantly decrease your fish’s resistance to disease and will ultimately lead to poor health and death.

The three main environmental stressors are temperature, pH, and dissolved oxygen. Temperatures outside of the optimal ranges for the species of fish being kept (below 16°C or above 32ºC) can shock the fish, resulting in anxiety and possibly death. A sudden decrease or increase in pH could also be deadly for your aquatic inhabitants if not correct quickly. Dissolved oxygen levels are also important as aquatic animals need a steady supply of oxygen to stay healthy. When dissolved O2 is too low (below 5mg/l), it can cause adverse effects such as lethargy, reduced resistance to diseases, reduced growth rates, rapid breathing rate, and even mortality.

It is recommended that you monitor these factors on a regular basis with reliable instruments such as DO meters, salinity monitors and temperature probes in order to quickly identify any areas of concern which may affect your aquaponic environment as putting your fish under stress is counterproductive when attempting to build a successful aquaponic ecosystem.


Overcrowding can be a major factor in the stress levels of fish and other aquatic animals, leading to deadly outcomes for aquaponic systems. A tank that is overstocked can cause water quality to decline and eventually lead to the death of fish if immediate measures are not taken. The amount of stocking should be determined based on the size of the tank, filtration system, and individual species’ requirements. For example, some species require swimming room while others prefer more crowded conditions; overcrowding in these cases may not kill the fish, but it can still cause undue stress.

Signs that an aquarium is too crowded include:

  • Aggressive behavior between inhabitants
  • Stunted growth due to lack of nutrients or space for movement
  • Raised levels of ammonia or nitrites in the water due to waste build up
  • Excessive algae growth due to turbidity caused by overcrowding

To combat this problem aquarists should ensure their stocking densities match their tanks appropriately for both the species type and numers involved. Additionally good maintenance practices such as proper feeding regiments, adequate filtration systems, regular water changes and testing are essential for keeping water quality high and reducing stress levels in fish populations.

Poor Handling

Poor handling is one of the primary causes of stress for aquatic animals, such as fish raised in an aquaponics environment. Stressful situations can include injury due to netting, water temperature or chemical changes too severe for the fish to handle, and excessive handling/moving from tank-to-tank. When a fish is stressed, their immune system weakens and creates an environment where it is more likely to fall victim to parasites and disease.

Some common signs of stress in fish include decreased appetite, rapid gill movement, clamped fins and lethargy. If left untreated, these stressors can develop into more serious problems including infection and death.

The best way to address these issues is prevention; aquaponic system owners should ensure they use proper netting techniques when transferring fish from tank-to-tank and that they check all water parameters regularly to avoid any sudden fluctuations. Additionally, providing aquarium decoration will provide hiding spots for the fish so they don’t feel overly exposed or vulnerable when being fed or moved around in the tank.

Similar Posts