What Is The Aquaponics Fish To Plant Ratio?

When starting with aquaponics farming, the first thing that demands concern is preparing the aquaponics fish tank. The question often dangles—for beginners and veterans, what is the aquaponics fish to plant ratio? 

Before answering that question, one must know that such proportions depend on planting density, biofilter size, bacteria cycle, and fish stocking density. Any mishandling due to a lack of proper information in these parameters can be fatal for both the fish and plants in the aquaponic ecosystem. 

This article strives to help growers determine the right aquaponics fish to plant ratio as part of their sustainable farming project.

Specifics of Aquaponics Fish to Plant Ratio One Must Know

Before diving into the fish to plant ratio, let’s understand how the aquaponic ecosystem works. That might give you an idea of the importance of the fish to plant ratio. 

When you feed the fish with quality feed, the fish excretes ammonia as their waste, making way for fertilizers for the plant to use. The good bacteria break down the ammonia in the water into nitrate that the plants readily absorb. The plants, in turn, purify the water to allow fish to sustain themselves.

Now, there are a lot of factors at play here: the size of the plant, the perimeter of the grow bed, plant density, and aquaponics fish to plant ratio. Some plants may require a bigger quota of fish-produced fertilizer and may not receive it due to the under-sufficiency of fish to plant ratio. This will lead to the plant’s under-growth and probable demise. 

In crux, the importance of ensuring the right aquaponics plants to fish ratio while preparing an aquaponics fish tank is as follows:

  • The correct number of fish per plant can provide proper nutrition flow in the ecosystem.
  • The plants can keep the water purified and aerated for fish health.
  • The good bacteria in the fish tank can contribute mainly to both the fish and the plant in the ecosystem.
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Does Aquaponics Need To Be Covered?

Not covering your aquaponic setting might seem intuitive, but it couldn’t be farther from the truth. Here are some reasons you should:

Preventing Algae Growth

Sunlight is a catalyst for the growth of aquaponics plants. If it’s allowed in the water, it’ll cause algae to grow. The aquaponics fish tank has a wider surface area, and the aquaponic ecosystem. And if that area were to receive sunlight, the algae would thrive like mini-plants in the water. 

They would form another ecosystem inside the water where these mini-plants would absorb nutrients from the water and leave nothing for the actual plants to grow. Moreover, the algae will suck up all the oxygen from the water, leaving nothing for the fish. 

Maintaining pH of the Water

As the temperature goes up, it alters the water’s pH, causing it to become more acidic. The reason is that the more the temperature rises, the easier it is for water molecules to disintegrate into hydrogen ions. And if this happens, all life in the aquaponic ecosystems will bear the brunt. 

Likewise, when it rains and enters the aquaponic fish tank, it makes the water more acidic. Rainwater is relatively acidic and tends to alter the pH of the tank water. Simultaneously, the water going through nitrification (good bacteria breaking down the ammonia into nitrate) is already acidic. The effect doubles up and kills both the fish and the plant. 

How Big Of An Aquaponics Fish Tank Do I Need?

The surface area of water plays a vital role in ammonia conversion to nitrate. The bacteria are present in colonies over the water surface, responsible for converting their share of fish waste in that area. Therefore, using the right quality of growing media can influence a healthy bacteria colony. Hence, choose a fish tank that is optimal in size for the grow bed and the number of fish.

We recommend using 1 kg of fish per 50 litres of grow bed in a perfect situation. Note that the determination of fish tank size depends on your requirements and suitability as per the above factors. However, ideally, the grow bed ratio to the fish tank should be equal, i.e., 1:1. But, if you want to go commercial with a supported number of fish in the tank and controlled environment, you can go as far as 2:1 or 3:1. 

Aquaponics Fish Tank

How to Determine the Right Fish to Plant Ratio for Your Aquaponics Fish Tank?

As mentioned above, several factors determine the fish to plant ratio for your aquaponics fish tank. This section will list significant factors that determine the percentage. 

Plant Choice, Grow Bed Choice

Our environment is abundant with different plants. They all have different growth spans, growth sizes, and nutrient requirements. Growing high nutrient-requiring aquaponics plants like tomatoes and cucumbers on a low fish number with smaller fish tanks can worsen the aquaponic ecosystem. 

Choosing a plant to grow in a controlled home aquaponic environment with an average fish tank must go with low nutrient-requiring plants like lettuce, cabbage, herbs, peas, etc. 

Fish Breed Choice

Fish that are low maintenance but have higher, nutrient-rich waste is the right choice. Tilapia, carp, goldfish, and koi are the breeds that can survive even if the water quality plummets. They are hard to break and easily stock in numbers for higher waste yields.

The density of stocking the fish into a tank shall also be considered carefully. Be mindful that fish are also organisms with competitive behaviour. Stocking larger sizes of fish with smaller dimensions can lead to them killing each other off. Stocking in large numbers might also cause nitrate bursts and oxygen shortage and be fatal for survival. 

Feeding Rate Ratio

How much and what you feed is directly proportional to fish waste production. They use upto eighty percent of their food and excrete only twenty per cent. So if you have a grow-bed full of leafy vegetables, feed your fish 40-50 grams per square meter per day. And if you have fruiting vegetables, feed them about 50-80 grams per square meter per day. 

The Bottomline

Based on the provided intel, you should be able to determine your fish to plant ratio for your home aquaponics. Rising global temperatures have proved highly sustainable farming cultures like aquaponics. So if you are a sustainable farming enthusiast and looking to establish your first aquaponics fish tank, be mindful of the above points. 

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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.