Rainbow Trout in Aquaponics

Aquaponics is basically the combination of aquaculture and hydroponics. In short, it requires you to nurture fish or other aquatic life. The by-products of these fish are microbes and waste. These are perfect as food for plants.

The plants then consume the fish waste and filter the water, providing the fish with a clean environment in which to live and breed. Aquaponics has been used for many years to encourage better plant growth. It is particularly effective in areas with poor soil quality.

In fact, aquaponics can help you to avoid the issues that often ‘crop up’ (pun intended) when using soil-based plant growing methods. These include issues with pests, weeds, and insects as well as getting the watering schedule right.

Of course, hydroponics (growing plants in a balanced water solution) isn’t perfect; you still need to balance man-made chemicals and monitor the water regularly to ensure it is safe and helpful to your plants. You’ll also find that the water in a traditional hydroponics set-up will need to be changed often. This is why fish have been added to the equation to create aquaponics.

Suddenly you don’t need to control all the elements of your water mixture. Simply feed your fish and allow them to take care of your plants for you.

In fact, once you understand the process you’ll find it can be done even in your garage with the right equipment, attitude and time. Adding fish to your aquaponics system can make it much easier to grow any kind of plant.

Get Started with Aquaponics

I have written a book that contains all the information you need to get started with aquaponics.

Don’t be the person that makes painful mistakes during your first aquaponics build!

It has 265 pages filled with information about aquaponics. It’s available in paperback or eBook format.

You can buy it here on Amazon.com

Why use trout?

Trout is undoubtedly the most widely farmed fish in the world, majorly because it is a prized food fish and is comparatively easier to culture.

Trout aquaponics can successfully grow trout fish right in your backyard or garage and isn’t it great to grow your own dinner?

Rainbow Trout in aquaponics

There are actually many different types of trout but the 3 main species are:

  • Brook – Also known as speckled trout it is generally found in cold water streams that border the mountains.

brook trout for aquaponics

  • Rainbow – These are perhaps the prettiest of the trout with a pink stripe, an array of black spots and a pink or red cover over their gills. They are also found in cold mountain streams but are much better at dealing with a variety of temperatures.

rainbow trout for aquaponics

  • Brown – These are actually European trout. Unsurprisingly they are brown in color. They also have a splattering of spots; ranging in color from black to red and even orange.

brown trout for aquaponics

The best one of these to use in your aquaponics system is the rainbow trout.

This isn’t because they are the prettiest or generally the toughest fighters. The simple fact is that rainbow trout are the strongest type of trout. This makes them easier to grow for farming purposes and much less maintenance for plant growing purposes.

Trout are generally fast growing, allowing you to increase your population. This can be useful if you want to sell the fish to generate additional funds or simply enjoy eating them.

But, the real reason to choose trout for your aquaponic setup is that their speed of growth will allow you to rapidly increase the number of crops you can grow.

The key element to choosing rainbow trout is that they can survive in a fairly wide range of temperatures; maximizing the production of nutrients to help your crops grow.

It is a good idea to consider Trout Fingerlings for Aquaponics. The first reason why this is a good idea is that the cost of purchasing fingerlings is significantly less than getting full-grown rainbow trout.

But fingerlings are also more adaptable. They will respond to the climate you have created and flourish in it; even if it is not optimal for adult trout.  This doesn’t mean that you can have any system; you still need to monitor the ph levels and other chemicals.

Fingerlings are also incredibly good at creating waste; mainly because their digestive systems are still developing.

By adding fingerlings to your aquaponics you can increase the number of nutrients available for your plants; this will either increase the yield from your crop or increase the number of plants you have!

Pro’s of trout in aquaponics

  • Low maintenance – When it comes to keeping the fish healthy there is very little you need to do with trout. They are the ones who can pretty much take care of themselves without added help.
  • Fast growing – They grow really fast. How fast? Marketable sized trout can be reached in about 9 months ( ~40 cms). The ‘pan-sized’ ones take about 12-13 months, which is pretty fast compared to other fish. Thus you can grow them fast and start the new cycle really soon as well.
  • Excellent food conversion ratios – The maximum weight of the fish can be safely consumed and is rather delicious. Also, since the diet of trout consists of mollusks, flies, and crustaceans which are high in energy, lipids and fish oil (great for cholesterol); it all gets reflected in the nutritional value of the fish itself.
  • Great for cool temperatures – Living in cool temperatures? Don’t you worry, trout are here for you! They prefer water temperatures between 10 to 20 degree Celsius.

Con’s of trout in aquaponics

  • Large area required for their growth – Trout requires fast flow rates to be cultured at high densities and thus if you wish to grow trout, it is better to do so in large systems no more than 0.5kg per 100L of water.
  • High temperatures – Trout has the capacity to withstand temperatures between 0 and 22 degrees Celsius. However, optimum growth occurs only between 12 and 16 degree Celsius. Water temperatures above 22 degrees make the digestive system of trout inefficient and most of the feed will end up as waste.
  • Low oxygen levels in the water – If the water has oxygen less than 5.5mg/L. So, in case the fish stocking density is too high (usually it is not) then it will be difficult for the fish to thrive as they need high oxygen levels in the water to survive.

Trout in aquaponics and aquaculture

If you are keeping fish it is possible to have them swimming around at the bottom of your plants. However, there are two concerns with this approach.

  1. The fish need cool water; your plants may prefer warmth making it difficult to get the right balance.
  2. It’s possible the fish will nibble at the roots of your plants; potentially ruining your crop.

The solution is actually very simple. You already know what PH, temperature, and size of tank you need to keep your trout happy. Create this pond separate from where you are growing plants. Then simply use a pump to circulate the water around the system.

The fish will be kept healthy in their pond while their waste will effectively feed your plants.

You should also be aware that with aquaponics you will lose about 1% of your water to evaporation and to the plants; they do need to consume some! This is significantly less than all other methods of growing crops.

You’ll be saving money on water costs and nutrients while helping the environment and getting better quality crops!


It is important to cycle your aquaponics system before you start to use it. For example, if you are looking to grow marijuana then you’ll want to create a bedding area for your plants above the fish water. You must then add approximately 2ppm of ammonia to the water and allow it to cycle until the nitrogen levels and ammonia levels become zero.

At this point, the water should have plenty of nitrates which are the bacteria responsible for turning fish waste into plant food.

Only when the water has enough nitrates can you start to introduce your trout and know that the bacteria will provide enough food for your plants.

This is actually true for most types of plants. You can even use trout aquaponics and a process known as the dual root zone to ensure your plants have all the nutrients they need. The better the system is at supplying the necessary nutrients the less work you’ll need to do to produce your crop.


All in all, it is a great fish to cultivate. Trout Aquaponics is done at many places all around the world, especially in colder countries. It is low maintenance, the fish diet is easily available and they grow pretty fast, so not much waiting.

Trout aquaponics can provide you with healthy fish to eat but it is even better at providing you with a healthy crop of your chosen plant.  That’s the biggest benefit of aquaponics; you’re improving the environment while growing your favorite plant.

Read more:

Get Started with Aquaponics

I have written a book that contains all the information you need to get started with aquaponics.

Don’t be the person that makes painful mistakes during your first aquaponics build!

It has 265 pages filled with information about aquaponics. It’s available in paperback or eBook format.

You can buy it here on Amazon.com

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