5 Tricks To Reducing Fish Stress

5 Tricks To Reducing Fish Stress

It’s the little things in life that will kill you.

Many fish can tolerate a few improper conditions in the fish tank, but just because your fish are alive, don’t think they aren’t being affected. Improper tank conditions often result in fish stress. And when fish are exposed to several seemingly small  improprieties, that stress can end up compounding and weakening the fish’s ability to deal with further problems. Fish that are stressed are more susceptible to parasites and disease, have weaker immune systems, and are less likely to recover from any mistakes made as a fish caretaker. 

Stability is a common theme in preventing fish stress. Fish don’t require everything to be perfect, but if your tank conditions are rapidly shifting back and forth, your fish are never even able to adapt the stress they are being exposed to. That said, a lot of what we can do as fish farmers to reduce fish stress revolves around observing their environment and taking measures to remove chaos and provide stability. 

Here are a few quick tips on how you can reduce the stress load for your fish:

Add Supplemental Lighting: 

In an outdoor aquaponics system, lighting isn’t too much of a wild card. The sun rises and sets every day, gradually getting lighter, then darker as the day progresses. In an indoor environment such as a house or garage, however, this may not always be the case. As people move in and out of the room, the lights tend to frequently be flipped on and off. Because fish have a deep rooted instinct to hide from predators, sudden bursts of light can lead to them feeling exposed and at risk.

If you are raising fish indoors, make sure your fish tank has its own individual light source. A separate light source will will provide stable lighting for your fish environment and neutralize much of the effects of the surrounding lighting. Having separate lighting can also give you control over your fish daylight schedule, which you can adjust to increase their growth rates and metabolism. 

Raise Your KH: carbonate

KH is a measure of your water’s carbonate hardness. pH is a common stress factor for fish; fish can tolerate a fairly wide range of pH, but they are very sensitive to rapid pH changes. Carbonates work as a pH buffer by neutralizing acids before they alter your pH, making your system less vulnerable to pH swings. This can help us by: one, reducing the amount of pH maintenance to our system (less maintenance means less room for human error) and two, protecting our system against sudden falls in pH.

In aquaponic systems, it’s fairly common to alternate between calcium carbonate and potassium bicarbonate for the dual purpose of raising/buffer your system pH, as well as providing extra calcium and potassium.

Insulate/Cover Your Fish Tank

Temperature swings cause fish quite a bit of stress and makes them particularly susceptible to white spot disease, or ick. Outdoor systems are particularly susceptible to temperature swings as the earth heats and cools with the sun. To help stabilize your temperature, try to insulate your outdoor fish tanks by burying them partially in the ground or by covering them with foam boards.

By the way, the store here at Frosty Fish carries plans and materials for making fish tanks out of freezers. In my opinion, it’s a great way to get some extra insulation and keep some extra chest freezers out of the garbage dump. Definitely worth checking out!

calciumchlorideSalt Your Tank:

Aquaponics is centered around the nitrogen cycle. Fish waste is given off in the form of ammonia, which is then converted to nitrite, and ultimately nitrate. Fish can handle large amounts of nitrate, but if we accidentally overwhelm or interrupt our nitrogen cycle, then our fish can be exposed to unsafe levels of toxic nitrite.

Try salting your system annually with 1ppm of chlorides. Chlorides reduce nitrite toxicity for fish and can also be a great vehicle for adding some extra nutrients to your grow environment. Sodium chloride is acceptable in small amounts, but I prefer using calcium or potassium chloride for the extra nutrients they provide.

Atria Aqua Gardens actually sells a pre-mixed blend of salts specifically for aquaponic systems. You can check that out here: http://stores.atriaaquagardens.com/fish-and-plant-beneficial-aquaponic-salts-for-100-gal/

Deal with Algae:

Although you may not realize it, algae can cause more problems than simply being an eye-sore. Algae causes pH swings by removing CO2, which is a weak acid, from the water during the day. When photosynthesis stops at night, algae also removes oxygen from the water supply, creating dissolved oxygen fluctuations that can cause fish a lot of stress.

Sunlight and excess nitrates are common causes of algae. To reduce algae in your system, make sure you shade water that is exposed to light wherever possible and keep your nitrate levels low.


Once you start thinking about fish stress and how to remove stress-causing factors, you’ll begin to notice a huge difference in your fish’s attitude.  You’ll be amazed at what your fish can handle once they aren’t weighed down by all the tiny problems of tank life. They’ll be happier, healthier, and grow faster. And you’ll be happier too!

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