The majority of society thinks aquaponics is an advanced complex method of raising fish.
The truth is aquaponics is really not that complicated once you understand how it works, and how to maintain it. Aquaponics is a symbiotic system of aquaculture, and hydroponics.
Amazing, huh? The aquatic animals eat off the plants, and the plants receive food from the fish excreting waste. Fish are important in the aquaponic system.
Therefore, the health of the fish will ultimately depend on keeping the fish in the best conditions for the fish to thrive.
Consider the following at a minimum:
- Feeding
- Water pH
- System size
- Water temperature
- Nutrition
- Light and
- Hygiene
Caring for Fish in an Aquaponic System
Below is a comprehensive guide on aquaponics fish care to make your system a success.
Proper Fish Species
To keep your aquaponic system healthy and viable, it is important to have the best type of fish.
The most popular fish recommended for aquaponics are tilapia, carp, catfish, trout cod, salmon, and bass. Appropriate fish species will allow you to keep the proper conditions of an aquaponic system alive to keep fish alive.
Also, all your fish need to be compatible. For example, an aggressive fish will stress out other (non-aggressive) fish that will affect their health as well.
So, understand the compatibility of the fish species you choose and observe fish behaviors and habits, such as different swimming patterns and locations.
Water Temperature
Fish are unable to thrive in waters that are too hot or too cold because they do not regulate their body temperature like mammals do.
As well, different fish species require different temperature levels. Some fish are classified as cold-water species and others are classified as warm-water species.
Coldwater fishes typically do well in water temperatures at least 57°F. Warm water species thrive when the water temperature does not exceed 86°F. Rapid temperature changes are also detrimental to fish if they occur with too much change in temperature.
One temperature change can present a lot of stress for fish and ultimately lead them to result in an unhealthy position or even death.
Don’t Forget: You must make sure you change the water temperature to assure that you are making every possible effort to maintain an ideal temperature for the fish.
Water pH Levels
Measure the pH of your water weekly and keep it within a neutral range of 6.8 to 7.0.
To decrease the pH, add a pH down liquid, or use a pH up solution increase the pH. These are food grade solutions that have pH stabilizing properties and will not harm your fish.
Always make minor adjustments to your fish tank water until you reach your desired pH level.
Plant Health
In order for the fish to flourish, the plants need to be healthy.
Check for pests and diseases, and treat the plants if needed. Make sure you still have good space between plants and add fans in the room for air circulation and to help regulate room temperature.
Control plant overgrowth by harvesting your crops. Plants have different needs so you have to create a situation that is good for, and adjustable to, your plant’s specifications.
Fish Nutrition
Ideally, feed your fish 2-3 times a day. Avoid overfeeding. The general advice is to feed your fish only as much as they can eat in five minutes.
If any excess food is in the tank, remove it because excess solid waste can degrade water quality and is not good for the fish.
The food you choose to feed also needs to provide good levels of quality nutrition. Commercial fish feeds have sufficient protein, carbohydrate, fats, and minerals depending on the fish species.
Quick Tip: Do not buy fish meal-based feeds , they are not sustainable.
Aeration
The warm water decreases oxygen levels in the fish tank which puts the fish in distress.
Fish can die in just 30 minutes if they do not have enough oxygen. You will need to clean your air stones by soaking them in a diluted hydrogen peroxide solution and scrubbing the bio slime away with a brush.
You want to check your aerator several times per week to make sure it is functioning properly, especially if you live in a warmer climate you can even install a second aerator.
Always be prepared to have a backup source of power for your pumps and aerators.
Water Quality
Keep a close watch on your water quality on a regular basis to make sure that the fish are healthy.
Add water or do partial water changes with temperate, dechlorinated water to remove any sedimentation at the bottom of the tank.
The accumulation of too many solids in a fish tank will lead to an overgrowth of heterotrophic bacteria that breaks down solids, which affects your nitrifying bacteria by taking up space and oxygen.
This will lead to denitrification which reduces the nitrates that plants need.
Ammonia and Nitrate Levels
It’s best practice to check your aquaponic fish tank for ammonia and nitrate levels once every month.
The acceptable levels of nitrates are below 150ppm and ammonia levels should be at or below 0.5ppm. If you have poor cleanliness, feed your fish too much, or overstock your fish, your nitrates will increase.
High nitrates will limit the amount of nitrogen released by the nitrifying bacteria that your plants can access.
Here are some ways you can eliminate nitrates from your system:
- Change 25-50% of the water
- Reduce feeding
- Remove excess fish food,
- Clean the tank
- Increase aeration.
Hygiene
One thing you have to consider while using a fish tank is the cleanliness of the tank in order to reduce the risk of disease in your fish and in your plants.
Here are 3 easy steps.
- Clean out the beds when you change the plants. I mean, just dump out the water and fill in de-chlorinated water.
- Check the plumbing. Remove any clogs.
- Clogs will have pressure, and consequences for proper water flow.
Also, you should consider replacing broken parts at this time.
Promote Nitrifying Bacteria
Fish generate waste into the water as ammonia, and bacteria consume fish waste and produce nitrite.
Nitrites are not safe for fish, and nitrifying bacteria convert nitrites to nitrates. Nitrates are the main source of plant nutrition.
The nitrifying bacteria performs slow in temperatures lower than 60°F and greater than 80°F. This slows down the conversion of ammonia and nitrites, and you end up with a ton of waste in the fish tank.
To remedy the situation, you need to deep-clean the fish tank or purchase some nitrifying bacteria to protect your fish from nitrite poisoning.
Prevent Growth of Algae
Prevent algae from growing in the aquarium because they will increase the competition for nutrient and oxygen.
Place your fish tank and sump tank covers and avoid direct sunlight.
Pest Control
Inspect around the base of the plants for aphids, whiteflies, and other pests at least once a week.
Mix together white vinegar and water to make a homemade pesticide and spray around the plants.
Do not use pesticides that have neem oil or pyrethrum in them, even though they are organic safe for plants, they are toxic to fish.
Final Thoughts
Taking care of your fish properly is critical to obtaining the maximum benefit from your aquaponics system.
There is a very fine balance of temperature, pH, aeration, water quality, and light levels inside the fish tank to keep your fish happy and healthy.
Now that you have some tips, you can create the best possible environment for your fish. You can even start with a small aquaponic ecosystem like this one.