Aquaponics UK, with the help and hard work of two fantastic interns – Laurie and Nico, designed and built an aquaponics system for the Nepal Youth Foundation in Kathmandu. The project was funded primarily by Rotary Club Bruxelles – Forêt de Soignes, with support also from Rotary Clubs of Versailles and Heidelberg and the Rotary Foundation. NYF are a pioneering charity that provide homes, healthcare and education to impoverished children across Nepal. The aquaponics system is located adjacent to one of NYF’s Nutritional Rehabilitation Homes (NRH) which restore severely malnourished children to good health whilst educating the mothers about nutrition.  The system was designed to be low-cost and to use only locally available materials. It uses passive solar greenhouse technology in order to reduce heating requirements and to enable year round production. This is a trial project that will inform replication across Nepal in both urban and rural areas. The system will be used for training of both staff and local people to encourage enterprise and the produce will be sold to provide income to the charity and used in the NRH.

You can find out more about the NYF here

So have a look around, hope you enjoy and look forward to hearing your comments…

The basic principles of aquaponics are as follows:
Fish and plants are grown in a symbiotic balance. Wastes from the fish provide nutrients for the plants, and in turn the plants filter the water for the fish. Plant off cuts can then be composted in wormeries to provide food for the fish and so the cycle continues… Crops are constantly harvested and the system feeds and watering itself in a sustainable ecosystem approach to food production. Surround the system with a greenhouse, add lady birds and other beneficial insects and a microcosm is born…

WHAT

• A sustainable way of farming food using very few inputs to produce a wide range of healthy and high value foods all year round.
• The growing of fish, or other aquatic organisms with plants in a controlled environment, optimising energy, water and nutrient use to produce the maximum amount of protein and vegetables in a given area.
• Fish wastes provide nutrients for the plants which in turn act as a harvestable filter system, cleaning the water so it can be continuously recycled. Off-cuts from plants are composted and the worms fed to the fish creating a completely closed-loop production system.

WHY

• 90% less water use than conventional agriculture.
• Combined technologies minimise energy use & systems often incorporate renewable energy technologies.
• Closeness to markets: freshest food with minimal transport emissions.
• No fertilisers or herbicides required & pesticides are replaced with biological control.
• Fish meal replaced with worms and insects from composting of plant off-cuts.
• Maximum plant densities and year round growing = huge yields.

WHERE

Aquaponics can be described as ‘closed-loop’ production in that it has the capacity to provide all  inputs to the system within the system itself and to recycle its own wastes. For this reason the applications of aquaponics are almost endless… it does not require fertile soil or large water inputs and so can be practiced almost anywhere. The ecosystem approach to farming lends itself well to conservation and development projects and also to education. Systems provide interactive hands-on learning environments and offer a wide range of activities for learning and teaching in multiple subjects, carrying with it important principles about natural cycles, farming and recycling.

aquaponics_systems

The practise of farming aquatic organisms such as fish, shellfish and aquatic plants is known as aquaculture. In recent years, the decline of wild fish stocks, combined with an ever increasing population has highlighted the shortfalls of capture fisheries and has resulted in massive growth of the aquaculture industry at 11% per year. In 2008, the global human consumption of fish and shellfish was 52.5 million tonnes, worth US$98.4 billion.  Such is the demand for healthy sources of protein (in particular omega 3 fatty acids) that it is now estimated aquaculture accounts for half of that fish and shellfish consumed by humans globally. In some countries such as China, this figure is much higher- with over 80% of fish for human consumption coming from farmed sources.

The concept of aquaculture is simple; to produce your chosen species with minimum input and in minimum time. To do this you must understand the influences that affect the growth of the organism. This principle is shown below:

All of these influences can be managed in some way and it the effective management of these which leads to successful aquaculture:

 HISTORY OF AQUACULTURE

Aquaculture is by no means a recent concept. Across the globe, pockets of aquatic production have been going on for literally thousands of years. Indigenous people from Australia may have grown eels in large volcanic floodplains as early as 6000BC as the main part of their diet. It has been well documented that in Far Eastern countries, growing various eels and carps in paddy fields along with rice began around 2500BC. Europe also has a long history of aquaculture, with the Romans and early Christian monasteries growing fish in ponds thousands of years ago.

During the industrial revolution, improvements in transport meant fresh fish could be supplied from the coast to inland areas relatively inexpensively, making aquaculture less popular. However, that same industrial revolution has now led to overfishing of wild stocks and a global population boom- which demands more fish. Over the last 50 years, this has made aquaculture a truly global industry, growing faster than any other food sector.

Growth of the aquaculture industry in such a short time has inevitably led to questions of sustainability. There is widespread acceptance that aquaculture will be relied on more as the global population continues to grow, therefore to provide in the future it must, and is, moving towards sustainability.

Examples of sustainable practices include: 

• Culturing ‘Vegetarian’ fish
  Fish lower in the food chain (carp, tilapia and catfish) can be fed a vegetable based diet in contrast to higher level species (salmon, tuna, cod) which must be fed a diet high in fish protein. 
  
• Improvements in feeding efficiency
  Improving the composition of feeds (by reducing the amount of fish meal), selective breeding of fish more efficient in converting food into flesh, and improvements in feeding techniques to reduce waste. 
  
• Closing the lifecycle of species in captivity
  So there is no need to gather new stock from the wild
  
• Supporting local communities
  Protecting natural ecosystems and improving the social and economic prospects of local people
  
• Reducing or eliminating waste output
  Integrated farming systems such as aquaponics, moving away from only farming one species at a site to an ecosystem based approach to production. Waste products from one species can be used to produce another. In this way various species from different levels in the food chain can be grown together. This can result in zero waste emissions, many different crops at harvest and crops that are harvestable at different times.

The Farm Animal Welfare Council (part of the DEFRA) was set up to ensure that any animal kept by man is at the very least protected from unnecessary suffering. A list of provisions that should be made for farmed animals to ensure both their physical and mental fitness was laid out in the form of Five Freedoms to be adhered to. The Five Freedoms have been widely used in marketing and have been the foundation of much legislation concerned with animal welfare both in and outside the UK. Although developed for terrestrial farms, these rules also apply to aquaculture as shown below: 

A large variety of aquatic species both cold and warm water; have been successfully cultured in aquaponic systems, including tilapia (Oreochromis spp), rainbow trout (Oncorhynchus mykiss), African catfish (Clarias gariepinus) (Arctic char (Salvelinus alpinus), barramundi (Lates calcarifer), European perch (Perca fluviatilis) , yellow perch (Perca flavescens) common and koi carp (Cyprinus spp), goldfish (Carassius auratus) and crustaceans such as red claw crayfish (Cherax quadricarinatus) and giant freshwater prawn (Macrobrachium rosenbergii). Tilapia, particularly O.niloticus is the most common fish cultured in aquaponics by far. Its tolerance of fluctuating water conditions and crowding, omnivorous diet and resistance to disease lends itself well to aquaponic conditions.

Click on the fish species below to find more information on culture conditions:

Nile Tilapia                        Common carp

Barramundi                       Yellow Perch

Rainbow Trout                    European Perch

African Catfish                 Giant Freshwater Prawn

Arctic Char

In its simplest definition, hydroponics is growing plants without using soil! In soil, plant roots receive all the mineral nutrients, water, gases and physical support they need from the soil but plants need to expend a lot of energy to maintain access to them.

Examples of hydroponics: (clockwise from top) rooftop vertical hydroponics, commercial- scale hydroponics, kitchen-top hydroponics.

In today’s hydroponic systems, many of the biggest challenges faced by plants (such as maintaining  access to water and nutrients within a soil) are totally taken care of. Hydroponics systems deliver water containing the exact proportions of dissolved, mineral nutrients, right to the plant’s doorstep; whilst providing all the other requirements for healthy plant growth.

This means that the plants growing within a hydroponics system can divert all the extra energy that would have been used to maintain access to water and nutrients within a soil to growing more leaves, flowers and fruits- in short, the bits that we as humans like to use! The result is that the plants produce more, with fewer inputs, in less time and with less space, which are just a few of the reasons why hydroponics is being adopted around the world for commercial and home food production…

Hydroponics: A Brief History Up to the Present.

The word ‘hydroponics’ comes from the Greek ‘hydro’ (meaning water), and ‘ponos’ (meaning labour).

The historical roots of hydroponic gardening go deep into history and indeed are the stuff of legends! The mythical Gardens of Babylon, the much worshipped flooding of the Nile in Ancient Egypt, and The Floating Gardens of the Aztecs are all examples of ancient hydroponics.

The ‘modernisation’ of hydroponics began in the 1600’s with relatively simple, scientific experiments to deduce the basic requirements for plant growth. Throughout the 17- and 1800’s, more specific experiments were conducted to further our understanding nutrient, water and gas cycles within plant growth, and to discover how soil could be replaced by other materials . The biggest leaps in hydroponic knowledge were made in the 1900’s. The work of several people, Dr Gericke is notable amount them, paved the way for the first large, commercial scale hydroponic installations… In the 1940’s, the US Air Force decided that it needed a way to grow food for itself on hard-to-reach pacific islands which were rocky and had very little soil. The US Air Force decided to go for hydroponics system and managed to produce enough fruit and vegetables to sustain hundreds of their military personnel! Today, hydroponic systems are a real hit with commercial market gardeners: approximately 90% of all cut flowers purchased in the UK, and 65% of all fruit and vegetables purchased in the UK are currently grown in hydroponic systems. The development of hydroponic systems continues to this day.

What Are the Benefits and Limitations of Hydroponic Gardening?

Hydroponics can boast some big benefits over more conventional, soil-grown crops. Some of the benefits of growing plants with hydroponics are:

• Plants can be grown in regions that were previously out of bounds due to a lack of suitable soil: this means inside big cities, dry deserts, or arctic research stations…
• The amount of water and fertilisers required is significantly reduced. Much of the water and fertilisers applied to fields simply evaporates or flows past the plants into ground water or rivers.
• Much less of the plants available energy is directed into growing big root systems that actively search out water and nutrients. All the water and nutrients a plant needs are right below it. This results in a more efficient use of space and significant improvements in the development of upper foliage, flowers and fruits.
• Weeds, the arch nemesis of many traditional gardeners, are almost non-existent (and the same can be said, of most pests that can only walk or crawl): weeding time is decreased; tea-drinking time is increased.
• Exceptional levels of gas exchange in the root zone as long as the water is fully aerated and the roots are never completely submerged. This also means that over- or under- watering is not an issue.

However, it’s not all fun and games with hydroponics! Here are some of the problems:

• Hydroponic systems rely on the careful and continual dilution of man-made nutrients into sterile water. This process requires that the all the nutrient levels within the water are continually monitored so that none reach toxic concentrations. This process is both expensive and time-consuming.
• The above notwithstanding, salts and chemicals inevitably build up to toxic levels, becoming wastes that need to be discharged. This creates the inconvenient and problematic issue of where to dispose of all that toxic water…

But, I hasten to add, the problems outlined above are all virtually none-existent in aquaponics due to the fact that aquaponic systems rely on a biological community to turn many of the problems inherent in hydroponics (otherwise known as wastes) into resources; this arrangement is opposed to hydroponics in that wastes are seen as just that, and thus are a problem! Consequently, aquaponic systems commonly outperform hydroponic systems: for further information on aquaponics outperforming hydroponics , see this article from the Aquaponics Journal: http://www.aquaponicsjournal.com/docs/articles/Greenhouse-Aquaponics-Proves-Superior.pdf . More information on aquaponics is available throughout the site, but for now, back to hydroponics!

What Are The Most Common Types of Hydroponic System?

Nutrient Film Technique (NFT) Systems:
NFT was the original hydroponics technique and it remains popular today due to its simplicity and cheapness.

The premise is that the plants are held above a table that is slightly slanted to one side. Water is pumped from a reservoir to the top of the table and allowed to flow down over the surface of the table in a thin film, 1-3mm deep. When the water reaches the bottom of the table, it is directed back into the reservoir to complete and completes the cycle. Nutrients and air are added into the reservoir.

The main disadvantages of this technique are that: the roots are constantly submerged in water, increasing likelihood of bacterial disease and reducing aeration of the root ball; their small pumps are prone to breaking; and because the roots don’t have much to cling to, big plants have a hard time standing up! However, despite the above, these systems are very productive, and as mentioned before, both simple and inexpensive. NFT systems are sometimes modified to support aquaponics.

Drip Irrigation Systems:
Drip irrigation systems grow plants in a rockwool slab. The plants are individually fed using drippers, which in turn are fed from a central reservoir. Commercial systems are usually fed under high pressure and only allow the water to circulate the system once; after that, the nutrients are bled-off and the water directed into a drain for disposal. Such systems dominate the Dutch horticultural industry. Domestic systems on the other hand are largely the same but are low pressure, and usually recycle their water.

On the plus side: drip irrigation systems are very versatile; productive; and cheap to build. On the negative side: running costs are high- the rockwool is replaced with every crop; nutrient losses are high if you run a system that goes straight into a drain after one drip through the rockwool; and high levels of maintenance are required on both high and low pressure systems. Not recommended for a beginner!

Deep Water Culture (DWC) Systems:
DWC systems are the simplest of hydroponic systems and evolved for domestic use. They are cheap, work well, but do require a fair amount of maintenance.

Essentially DWC hydroponic systems are all contained within one container with a lid. A hole is cut in the lid through which a plant is suspended by a plastic basket filled with clay balls. An air stone is placed in the bottom of the container which serves to: mix the nutrients with the water; cause spray to hit the clay balls above creating a moist growing environment; and of course, to aerate the water with oxygen. Once the roots of the plant have grown down below their basket, they will be continually submerged in water. Essentially, DWC systems grow plants in their own water reservoir.

On the plus side, DWC systems are extremely cheap to make due to their simplicity. However, there are two main disadvantages to DWC systems. Firstly, the roots of a mature plant are continually submerged and thus, are very vulnerable to water-logging and oxygen starvation if  the pump stops working or becomes clogged. Secondly, the containers for DWC hydroponic systems are generally not very big and cannot hold large volumes of water (maybe5- 10 litres). This means that the nutrient concentrations and pH level within the system can fluctuate very quickly, as can the water level depending. The result is that the system needs to be checked very regularly to prevent your plant from suffering. Unless you only fancy growing one or two plants, DWC systems are not recommended.

Flood and Drain (also known as Ebb and Flow) Systems:
A Flood and Drain does exactly what it says on the tin- it floods a grow bed (filled with a permeable media), and then drains it. The advantages of this system are that as the bed is filled with water old air is pushed out of the air pockets between the media; and as the water drains out, new air is pulled in- this means that aeration of the rootball, which sits in the media, is excellent, whilst access to water and nutrients remains high!

The grow beds are fed using a pump submerged in a large reservoir, located beneath the grow beds. The flood and drain pattern can be achieved in one of two ways. Either the pump is on a timer, meaning that it will pump water into the grow bed until it is full, after which time the water drains back into the reservoir under gravity. Or, the pump is on constantly and an automatic bell siphon causes the water level within the grow bed to continual fill and drain. Pumps that are continually turned on and off break more often than those that are continually on. Therefore, the latter method will probably be cheaper!

The flood and drain system is a real winner. It is very simple and effective! The only negative I can think of is that if you use clay balls as your media, they need to be washed before they are used to prevent clay dust engulfing every part of your system.
(This is the system most popular with home aquaponic gardeners!)

Aeroponics:
The theory of aeroponics is that the roots of a plant are suspended in the bare minimum of media and are continually sprayed with a fine mist of nutrient rich vapour. The misting action means that aeration of the water is second to none. This is all very well but the nutrients dissolved in the water tend to precipitate (separate from the water and solidify) around the mouth of the misters very quickly, rendering them useless- sometimes in a matter of hours! More modern aeroponics systems, to some degree, solve this problem by using a spinning, high-frequency sprayer which sprays the root ball from below. However, the high- pressure systems tend to blast fine roots into a tangled soggy clump whilst low pressure systems don’t generally deliver enough water and nutrients. The equipment is also fairly expensive. Although, despite these drawbacks, aeroponics systems can still deliver good results.

See more about planting in aquaponics here…

What Factors In A Hydroponic System Require Management?

The primary difference between hydroponic gardening and gardening in soil is just that; there is no soil. However, the majority of principles that apply to growing plants in soil-base systems also apply to growing plants in hydroponic systems. Therefore, it is the job of the hydroponic gardener to uphold and apply the normal principles of growing plants in soil, when growing  plants without soil! This requires that many environmental factors, such as the concentration of nutrients and oxygen within the water, are artificially controlled and managed. The factors listed below all require management:

• Nutrients:
  Nutrients are absolutely critical to raising healthy plants that reach their full potential. In hydroponic systems, plant nutrients are dissolved within the water- each nutrient at a different concentration according to their importance for plant growth. It is the job of the gardener to monitor and maintain these concentrations so that they remain at an optimum level for plant growth. Nutrient levels are measured indirectly using a digital EC (electric conductivity) meter. Nutrient concentrations are maintained within the water by the regularly dissolving a ‘nutrient solution’ directly into the circulating water (bottles nutrient solution can be purchased from any hydroponics equipment supplier).Nutrients can be divided into two groups: macronutrients; and micronutrients, also known as trace elements. Macronutrients are need in relatively high quantities; micronutrients, are needed in ‘trace’ amounts. It’s worth getting to know all of them and why they are important, and essential to know how to administer and monitor them. Below is a list of all the know nutrients know to be essential for plant growth, (describing the ins and outs of all them is beyond the scope of this article though, so we recommend getting a good book on the topic!):The macronutrients: Nitrogen (N);  Phosphorous (P);  Potassium (K); Calcium (Ca); Magnesium (Mg); and Sulphur (S).
  The micronutrients: Iron (Fe); Boron (B); Manganese (Mn); Zinc (Zn); Copper (Cu); Molybdenum (Mo); and Aluminium (Al).

• Water Aeration:
  The purpose of aeration is to dissolve as much oxygen into your water as possible! Plants absorb around 1% of their total oxygen requirement through their roots. In addition, a large dissolved oxygen concentration (DO) helps to keep the water free of pathogens and the roots to absorb nutrients.
  Good dissolved oxygen concentrations are achieved by placing aerators directly into the water (these blow bubbles into the water) and by breaking the surface of your water (as when water splashes from a tap into more water). Leaving the roots of your plants to dry out occasionally is a good idea too!

• Water pH:
  The pH value of a water body is a measure of how acidic or basic it is. pH is measured on a logarithmic scale of 0- 14: 0 being the most acidic; 14 the least. Water pH is important in hydroponics because it affects the solubility of nutrients within water, and thus influences how accessible they are to plants. As can be seen from the graph below, the majority of nutrients that plants require are soluble, and thus available to them, within a range of  pH 6 to 7 (width of bar indicates availability). It is worth noting that if  your growing medium is particularly alkaline, you should keep your water pH at a slightly lower level than normal to compensate. The pH of your water can be measured using either: paper test strips; liquid pH test kits; or digital pH meters.

• Temperature:
  Like all living things, temperature is crucial to healthy growth. Some plants like it cool; and some like it hot…:  knowing what temperature is best for the particular plants in your system (in both the air and in the water) is crucial to promoting healthy growth.
• Ventilation:
  Plants require carbon (C), oxygen (O), and hydrogen (H) to grow. They obtain the vast majority of these elements from gases in the atmosphere, so keeping your grow-room ventilated is very important. If you are growing in a closed environment, this will usually mean installing an extractor fan in the top of the room to pull stale air out; and a corresponding hole in the bottom of the room to allow fresh air in. If you are growing in a green house, leave some windows open.

• Light:
  Plants require light to photosynthesize- the more they have, the faster they can produce the food they need to grow and thrive. Lighting requires either that you use natural sun light, or that you buy specialised growing bulbs which emit the full spectrum of light that plants require. Care should be taken not to ‘burn’ plants by exposing them too much to the sun or to artificial lighting- the level of light required to burn a plant depends on the species.

When and how often do i feed?

When feeding always remember these tips:

1. Do not over feed
2. Observe
3. Remove uneaten food
4. Record sheets

A general rule for feeding fish is to only feed your fish as much as they will eat within five minutes. Spread the feed over the surface of the water slowly.  After five minutes, remove the remaining food from the tank with a net. Record how much you have given.

Over time you will be able to judge just how much food to give depending on their behavior, however it is strongly recommended you still watch them eat as this is an ideal time to inspect the health of your fish. Maintaining thorough records of your animals eating habits is invaluable. Over time this record will be able to tell you how if your fish are growing efficiently and allow you to improve production. If something goes wrong, consult your records; have the fish been eating less than they usually do? This may help diagnose your problem.

Generally it is  better to feed little and often, at least twice a day, ideally 3-4 times. You need to remember that you want all of the fish feed you give to be eaten; for two main reasons, firstly because its an expensive and valuable resource and secondly because if its not eaten then it will decompose and have a negative impact on your water quality

If you have different sized fish, and more than one tank, try and “grade” them into their same sizes to ensure they all get a chance to feed and if you have very small fish, you can change the type and size of feed as they grow.

As a final note, whilst your type of fish species will determine the type and presentation of the feed, if you can, its always better to feed a floating pellet as it allows you to have better idea of whats being eaten. As you will find out feeding is a really great opportunity to observe the health, condition and size of your stock, plus it gives a great early warning as to changes in water quality… so if they are not feeding normally, stop feeding, think why, and its often an indication to look further… (air, temp, pH, water quality, oxygen level etc.)

Which food for your fish?

The type of fish that are being grown, the age of the fish and the desired output from the aquaponics system will determine the amount and type of fish food that is used.
There is much choice, for a start: commercially produced pellets and other formulated feeds or homemade diets and even live feeds. A mix of all of the above? Knowing what your species nutritional requirements are and what you would like to achieve from your system will help you make this choice.

Commercial Feed

Providing its fresh and suitable for your intended fish species, then pelleted feeds provide a manageable solution to knowing exactly what you are giving your fish and therefore plants. Depending on whether the fish are omnivorous or carnivorous, they will require different protein levels (trout 45%, tilapia 30%), and depending on the size of fish, different sized pellets. In terms of presentation, they can be floating, slow sinking of fast sinking for bottom feeders.

In larger systems where desired output is high, a specific amount of formulated feed will give the best production possible. For a small system in the back garden, the grower may not require the system to be as productive and will be happy to use a general diet.
These feeds are excellent at providing the full nutritional balance your fish need and are of such consistent quality that the diet can be tailored so the fish to grow as quickly and efficiently as possible. The diets are also produced in such abundance (for the aquaculture industry and aquaria industry) that they are cheap to buy.
There is however often an ethical concern with these diets; many pellets contain high amounts of fish meal and fish oil. This means fish from the wild have been caught just to make the fish diet, sometimes more fish than would be caught in the first place for human consumption!

‘On-farm’ or home-made feeds made from wastes and resources that do not compete with human consumption can decrease the environmental footprint of production significantly.  Although more labour intensive to produce and ensure appropriate nutrient composition it can be a very satisfying process and create a more closed loop system. The following is a list of some of the feed that can be easily sourced or cultivated for most omnivorous fish:

Meal worms
A plastic container is filled with a couple of inches of substrate (wheat bran/oat meal), a source of water (carrots, potato, etc) and mealworms (obtainable from many suppliers). It is kept warm and old dried or mouldy bits of vegetable are carefully removed. In a few months the worms have grown large enough start to pupate. Some of the pupae kept and hatched into beetles. These beetles are kept in another container with the same substrate and water source and in a couple of months they produce tiny worms. These can be fed to your fish. As long as you leave some mealworms to pupate and produce new beetles, your colony should be fairly stable.

Artemia/Brine Shrimp
As the name suggests, brine shrimp need seawater so firstly seawater must be made, using sea salt made up as at least 36 ppt, about 25ᴼC and pH 8 or 9. Aquaria are best suited to producing brine shrimp and the eggs can be bought from many suppliers. After stocking the eggs, they take about 2 days to hatch into larvae. Phytoplankton is particularly good for feeding the larvae. Larger larvae and adults can be fed with: yeast, wheat flour, egg yolk and/or soybean powder. The adult brine shrimp are an excellent food source, particularly for newly hatched/young fish as they are high in nutrients and move about- triggering the fishes reflexes to eat it.

Black soldier fly larvae
The larvae of the Black Soldier Fly are voracious consumers of decomposing waste such as manure, green waste and cooked and uncooked food waste – basically they eat anything and reduce the mass and nutrient content of that waste significantly.   The larvae are a high quality source of protein, have a short life cycle and mature larvae even migrate from the feeding ground effectively harvesting themselves making them an ideal supplemental feed or on-farm feed ingredient. The fly is a tropical species so production units must be insulated over winter. A product called the BioPod is specifically designed for BSF food composting and through clever design, has the added benefit of self-harvesting the larvae.

Find out more here…

Earthworms
Earthworms, bloodworms, and composting worms all make excellent fish food and plant off-cut digesters! The leachate from wormeries and worm teas also make an ideal disease suppressant and supplemental foliar feed for plants. It is worth noting that some fish can, like humans and and our pets, be fussy eaters sometimes and it can be hard to get fish to eat pellets after a “live” food diet, and visa versa.. but something well worth experimenting with.

In summary
We recommend that you consider any one, or a combination, of the feeds above as a supplement to a standard pellet fish feed.  Nutrition for living beings is a complex subject, especially in outside of their natural environment. Just as we wouldn’t feed our dogs or cats exclusively a single, or even a couple foodstuffs, please consider feeding your fish a varied diet that includes a reputable, in date, pelleted fish feed suitable for the fish species you are growing.
Hopefully you have also picked up on the message that what you feed your fish, ultimately then feed your plants, and then going a stage further the amount and quality of the protein in the fishes diet, will directly effect the amount of dissolved plant food (ammonia-nitrates) that is produced into the water.

Aquaponics can be described as an energy efficient method of producing food particularly in comparison to conventional hydroponics and recirculating aquaculture systems. This is is partly due to conscious design choices which minimise energy requirements but predominately because the combination of the two techniques allow the energy costs to be shared. Two crops are effectively produced for the price of one.

Aquaponics systems on the whole operate within a controlled environment for year round production and this does necessitate an energy input of some kind particularly in temperate climates. Essential components such as the pump and aerators may be mechanically powered via a non-electrical means e.g. via foot , gravity or even play! (see: www.ideorg.org). This may not be possible however in larger systems or where a level of automation is required and so at Aquaponics Uk we strive to integrate renewable energy technologies with our systems wherever possible.  We are currently seeing rapid improvements in the efficiency and affordability of renewables which can easily be engineered into an aquaponics system.

The PDF below can help you answer some questions like:

• Which typical components of an aquaponics system which otherwise require electrical energy to operate?
• Why Is It Important to Integrate Aquaponic Systems and Renewable Technologies?
• How Do Aquaponic Systems Minimise Energy Consumption?
• How Can I Increase The Energy Efficiency Of My Aquaponics System?
• An Overview of a Few Renewable Energy Technologies Particularly Well Suited to Aquaponic Systems.

Energy Article