Fish Dying In Aquaponics: The Reasons And How To Avoid Them

There are a lot of aquaponic growers out there complaining about their fish dying constantly. I know it can be a little bit tough seeing one of the major elements of your growing system, which is fish, dying out of the blue. This made me want to write about it to educate future growers on the reasons why the fish die and how to avoid it happening.

So why do fish die in aquaponics? The main reason why fish die in aquaponics is due to a spike in ammonia and nitrite concentrations that reach toxic levels. Other reasons might be due to fungal disease or parasitic infections as well.

There are a lot of newbie mistakes that I see many growers fall into these days which result in the ammonia and nitrite levels skyrocketing. In this article, you will learn how to avoid these mistakes.

Ammonia Spikes In Aquaponics

It was simple back then when we were using hydroponics for growing plants. However, this is completely a different case when using aquaponics. Relying on fish to fertilize the plants is a highly complicated process.

Fish are living organisms that eat the food they are given to produce energy, and in the process, waste products are excreted. This as a result makes it extremely difficult to maintain healthy ammonia and nitrite levels.

So what causes the ammonia levels to increase in aquaponics? Ammonia levels tend to spike because of the absence of nitrifying bacteria inside the system.

Have you ever asked yourself how does fish live safely inside the same water that they excrete their feces in despite the fact that these feces contain ammonia which is extremely toxic? The answer is nitrifying bacteria.

The nitrifying bacteria are the main game-changer that plays a super important role in the nitrogen cycle in any ecosystem containing fish. Fish let go of their feces inside the water reservoir. These feces contain ammonia, which as I have said before, is extremely toxic. Here comes the role of these bacteria. The nitrifying bacteria transfer the ammonia into nitrates, which is a far less toxic substance than ammonia. Moreover, nitrates are a more easily absorbed form by the plant roots when compared to ammonia.

From the previously mentioned facts, I think that we have come to a conclusion that there can’t be a successful aquaponic system without nitrifying bacteria. Now comes a very crucial question, what newbie mistakes do growers do that harm the nitrifying bacteria in their systems?

Not Waiting Enough Time before Adding fish To The Aquaponic System

There is a huge mistake that almost every grower falls into when they are trying to set up their aquaponic system which is adding fish instantly after filling in their nutrient reservoir. This is usually known among growers as the new tank syndrome.

I know that due to the excitement at the beginning, people always rush and go buy a ton of fish to add to their system. However, this is completely WRONG and let me tell you why.

Nitrifying bacteria takes time to form a well-established colony in any fish tank. You can speed up the process by simply adding water from another fish tank that has been running for some time. Moreover, you can use stones and wood from other aquariums. These items tend to have pores on their surface which is act as a shelter for the bacteria to thrive.

So, the next time you are setting up your aquaponics fish tank, you will have to leave your system up and running for 4 weeks before starting to add any type of fish.

Overfeeding The Fish In Your Aquaponic System

There is a mindset among several aquaponic growers that if they feed their fish well, the fish will produce more feces as a waste product, and as a result, the plants will thrive. This is completely not true.

By overfeeding your fish, a lot of food will accumulate at the bottom of the tank. Over time, the accumulated food will start to break down and mess with the water chemistry. Nitrite levels tend to skyrocket when there is a lot of accumulated food in the tank.

Furthermore, overfeeding can cause diseases such as the fatty liver of your fish. Also, algae growth can be boosted if there is a sufficient quantity of accumulated food in the tank.

Low Oxygen Concentration In Aquaponics

Fish, like any other living organism, require oxygen to live. The lack of oxygen in an aquaponic system will lead to the fish suffocating and dying.

Having too low oxygen concentration can be a result of multiple things we do as newbie growers. One of the many mistakes that we do is overcrowding your fish tank with fish more than the capacity that your system can handle. This also can lead to an ammonia spike as we mentioned before.

Another factor that can decrease the oxygen levels in your aquaponic system is the low number of air stones available.

Different Temperature And pH Than The Hatchery

For us humans, a sudden change in our surrounding environment can severely affect our mental state and result in a lot of stress. This is not a completely different case for fish. Even worse, a sudden change in any of the variables in the surrounding environment will definitely result in fish’s death.

So, you have decided to go and buy a group of fish from the nearest hatchery or fish store to add to your aquaponic system. After a couple of days of placing the newly bought fish into their new home, you have noticed that your fish are starting to die one by one. Now you are wondering what have you done wrong that resulted in all of this.

Well, let me tell you what have you done wrong. The fish used to live at certain temperatures and pH in the hatchery that they were at, and after placing them in your system, they were exposed to completely different pH and temperature levels than the ones they used to live in. This sudden change will easily threaten your fish’s lives.

Common Diseases That Can Affect Aquaponic Fish

It can be a little bit confusing when you are trying to figure out whether your fish are dying because of a mistake that you have done or due to any type of disease. There are many diseases that can severely affect aquaponic fish, among these diseases are two major types whar are:

  • Ich
  • Fungus

Ich is a parasitic infection that infects fish. Mainly, it spread when you introduce new fish that has been already infected to your tank. lucky for us, it can be easily identified by the naked eye. You will usually find white spots and marks on the surface of the infected fish. It will take several life cycles for the parasite to spread to other fish in the system.

On the other hand, the fungus is a white cotton-like coating that can be easily spotted on the fish’s body. Usually, I will start to get suspicious about any fish if they start scratching their bodies against the tank rocks and walls more often. I like to think of it as their way of telling you that they are not okay.

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