Hydroponics With Fish: What You Need to Know

Fish hydroponics is increasingly becoming popular thanks to the environmental benefits and the ability to grow both plants and fish in the same place. Nowadays, many people prefer having their aquaponics systems with fish to get fertilizer for their plants. Farmers have proven that fish play a vital role in plant health by providing plants with vital nutrients to thrive. 

Investing in the hydroponic garden with fish may sound awkward, but it’s the best way to turn your hobby into earning without using much strength and energy.

Aquaponics enables plants and fish to coexist and is mutually beneficial for better growth. In a hydroponic system, you need to replace the aqueous solution after around two weeks. So, you can combine the two and have plants benefit from fish and vice versa.

If you’re coming across this concept for the first time, you’re in the right place. Here is everything you need to know about fish hydroponics. 

Can You Put Fish in Hydroponics?

Yes, it’s possible to have a hydroponic garden with fish. Fish hydroponics is much easier as the two will get mutual benefits, enabling you to harvest bumper while reducing your workload. 

But this doesn’t mean you won’t have a lot to do on your side. Remember, in hydroponics, you should replace the aqueous solution after about three weeks to minimize fungi, bacteria, and nutrient accumulation. 

On the other hand, you also need to remove the liquid solution in aquaculture to avoid fish waste, food, and toxic nutrients. Both require almost the same maintenance to have a clean setup and water.

The two can coexist and benefit from each other. A symbiosis relationship between fish and plants will result. The fish waste will turn from ammonia to nitrates after interacting with water. Nitrates are helpful for plants’ growth. The plants will purify the impurities in water, enabling your fish to get a fresh supply from the tank.

So, a hydroponic aquarium will significantly help you as a farmer and the plants plus fish as they’ll get a continuous mutual benefit. You will not have to replace the water regularly, reducing your utility bills. Not wasting water is also good for the environment, plus you’ll get a healthy and bumper harvest with little effort.

Aquaponics Fish

How Aquaponics System Work

You can make aquaponics of your preferred size, setup or complexity provided it meets your demands. However, you need to ensure the system has fish, plants, and bacteria for the symbiotic cycle to be complete. Below is how each element works in this cycle;

  • Fish produce waste products that act as fertilizers to your plants in this system. Before starting this project, you need to select the kind of fish to use to succeed.
  • Plants are biofilters in this system as they absorb nitrates and toxic compounds in the water, allowing fish to get clean water. This process prevents you from replacing the water regularly, reducing your water bills.
  • On the other side, bacteria help change the fish waste to nutrients that are good for the plants. This is done through the nitrification process, part of the nitrogen cycle.

How Nitrogen Cycle Takes Place

The nitrogen cycle in aquaponics happens in four major steps;

Step1: Ammonification: This is whereby fish release ammonia as a waste product from their respiratory system. Ammonia also comes from decomposed fish food and waste. A high concentration of this compound is harmful to the fish, and there’s a need to reduce its level.

Step 2: Nitrification: Nitrification should reduce the high ammonia level in the water. The nitrifying bacteria on the darker wet areas will aid in the aquaponic system. The bacteria will help convert ammonia into nitrite.

Step 3: Denitrification: The nitrites need to be converted to nitrates. Remember, nitrites are more harmful to fish than ammonia. Nitrobacter will help change nitrites to nitrates that are useful to the plants.

Step 4: Assimilation:  Lastly, the plants absorb the nitrates to help build their parts. This last step completes the cycle.

How Do You Make a Fish Hydroponics System?

Making fish hydroponics system is easy. You have to follow the below steps systematically. 

1. Install The Fish Tank

The first step you need to put up in an aquaponics system is the tank. The size of this tank should correspond to the space set aside for your fish. For example, if you opt for a bigger fish species, the area has to be larger, and the tank should be big enough to meet water demands.

The tank size also determines how you use the standard acrylic aquarium. But you can opt for a large barrel or food-grade container with opaque sides instead of this.

Install the tank, as you’d do with a normal fish tank. This means you have to dechlorinate the water and then stay for about 4-6 weeks before introducing fish into the system. The 4-6 weeks grace period enables bacteria to build up, which will help break down ammonia and the nitrites required for your plant’s growth.

But don’t forget to fix a pump that will circulate the water from the tank to the grow bed.

2. Construct The Media Bed

After fixing the fish tank, the next step you should do is to make the media bed. You can make it on top of the fish tank or beside it. The media bed or flood table is where your plants will grow.

To build the media bed, you can use a wooden pallet crate or a bigger high-density plastic tray then place it over a strong stand that can bear the weight.

After placing the media bed on the stand, add your preferred media. You can go for clay pebbles with a neutral Ph that doesn’t affect the water and can hold moisture. They are one of the most popular media for aquaponics use. Opt for a 1:1 ratio between the media bed and fish tank to have the same volumes.

Aquaponics Fish Tank

3. Introduce Fish into The System

The next thing you need to do is add fish into the system. The kind of fish to introduce will depend on your choice.

However, the common types people use for fish hydroponics system include;

  • Tilapia grows easily without requiring much care and hardly gets disease infections.
  • Goldfish will make the system have enough waste as they produce a high amount of trash for the nitrogen cycle.
  • You can also add koi fish for fetching good money as they’ve high market value.
  • Pacu is another the best choice for anyone looking for a beautiful fish for this setup.

However, other species like catfish, silver perch, carp, and barramundi can also thrive in this system. Consider the temperature, breeding habits, diet, and space available before settling for the type of fish to rear in this setup. Also, decide whether you want edible or ornamental fish and the maintenance requirements.

4. Bring In the Plants

After that, you need to set up the plants in this system to have a complete aquaponics setup. The leafy plants will grow faster, but you can also try introducing fruit plants like tomatoes if you have more fish. The easy to grow plants you can opt for are like basil, kale, mint, and lettuce

But if you’ve got a bigger tank and a better-established system, you can grow;

  • Beans
  • Cucumbers
  • Cabbage
  • Tomatoes
  • Peppers
  • Strawberries
  • Peas

It’s advisable to plant seedlings to reduce the growth duration. Also, be careful with their roots when growing on the pebbles and let the roots go deeper to reach nutrients and water.

5. Aquaponics System Maintenance

Once you have finished setting up this system, you need to look at the best way to maintain your fish hydroponics and have it last longer. First, you’ll have to get your fish quality food like flake food, but a treat after some days ain’t bad too. Note that giving the fish live food can bring infectious diseases to the system. So, avoid giving them such foods to be safe.

Only give them what they can finish up in not more than five minutes. Then have a feeding program like 2-3 times every day.

Apart from that you also need to check the water tank. Do test for ammonia, nitrates, and nitrates, plus the Ph levels of the water in the tank. The nitrites and ammonia levels should be low and undetectable. That of nitrates should be lower to show that your plants are making good use of it. The best Ph level should be between 6.8 and 7.0, which is neutral and encourages plants, bacteria, and fish growth.

Also, ensure you maintain the system’s Ph level as it reduces after the first cycle. You can alter the Ph level by adding potassium carbonate or calcium hydroxide powder to the tank. Don’t forget to check on your plants and remove weeds and any dirt around.

Aquaponic Plant

Advantages Of Fish Hydroponics System

  • It reduces water wastage
  • It encourages sustainable farming as there are no fertilizers, herbicides, or pesticides.
  • It allows you to harvest fish and plant simultaneously without much effort.


  • It’s expensive coming up with the whole hydroponic aquarium setup.

Bottom Line

It’s advantageous to start a hydroponic garden with fish to encourage sustainable living. There’s no use for salt-based nutrients in aquaponics as fish waste provides the plants with adequate nitrates for growth. With this guide in place, you can be ready to get started with fish hydroponics without much of a hustle. 

aquaponics experts

Welcome to The Aquaponics Guide

Hello! We are the Johnsons and the faces of The Aquaponics Guide. We have been avid gardeners for many years and growing our own food is one of our key priorities. We have found sustainable Aquaponics farming to be a life changer, which is the reason we have created The Aquaponics Guide. 

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