Animal welfare is essential.
The less stress your fish have to endure the better, keeping them healthy is important for their wellbeing, as well as your food production. Being able to see your fish is essential to aquaponics. At Aquaponic Life, we have paid a great deal of attention to our designs to replicate different species natural habitats.
SUBSTRATE AND TANK DÉCOR
Substrate and décor can bring several benefits not just in aesthetics but also in tank biology.
Although some fish prefer being shaded, having the ability to see your fish is incredibly important. You’ll quickly become aware of the natural behaviour of healthy fish and identify those which are struggling. Seeing potential problems early and taking suitable action will save time and money in the long run as well as giving the fish a better life. Fish swimming about in a beautiful well decorated setting is also very therapeutic to watch.
Aquarium gravel acts as a mechanical filter, and provides surface area for beneficial bacteria to colonise on. The top layer will collect algae, which the fish will suck off and eat, and it can also provide places for fish to lay eggs.
AQUAPONIC LIFE’S FISH BEHAVIOUR MONITORING:
We are absolutely certain that just as it does for us, habitat plays an essential part to animal wellbeing. The first simple experiment we ran on fish habitat, was to see how our Koi interacted with their environment. We monitored their behaviour firstly with with no substrate at all, slowly making additions until we had a completely aquascaped tank with aquarium gravel, rocks, aquarium wood, gentle current, caves and plants. Their behaviour in the bare tank was staggeringly different to that which was displayed when they were given décor/hiding places.
The fish became much more lively and interactive once we made the tank more naturalistic for them.
We repeated this experiment to make sure it was the same for other species, and we had very similar results; including watching the loaches change from always hiding behind the pump, to dancing about and sitting on rocks. Having correct habitat makes keeping fish much more fun and rewarding.
We highly recommend creating a naturalistic environment for your fish – It will be far nicer for you to look at too!
We decided to base our next habitat experiment on recreating natural currents for the fish to swim against, as they would in the wild. We felt this was especially important for the larger fish such as trout, which would naturally be found in rivers.
WHICH SUBSTRATES ARE SUITABLE?
Aquarium gravel from pet shops tends to be more expensive and a good size tank will take several bags, the benefit to buying pet shop gravel or sand is that it should be free from shells and coral that will affect water pH. There are many other sources of suitable substrate available at builders merchants or garden landscapers, but you need to make a couple of simple checks prior to using it.
Many fish eat algae off of substrate, such as carp which pick up gravel in their mouths and scrape algae off before spiting the substrate back out. Pebbles, stones, sand, leaf-litter and wood are also home to various bugs and critters which fish ingest as a source of nutrition. The right substrate can also be used to make nests or safe places for fish eggs to fall between, so substrate has many uses.
Choose a substrate that won’t leach chemicals or toxins, and they shouldn’t have any sharp edges which could harm the fish as they swim. Water pH can be raised, lowered or buffered (kept stable) through the use of different materials.
Lastly, the size of the particles is also important; too small and it will become clogged and anaerobic, too large and the surface area is reduced which means less space for biologically activity to thrive. Make sure it’s not too deep, a few centimetres will normally suffice as any deeper can lead to areas of anaerobic areas. We tend to use under-gravel filters to keep water moving through the substrate which prevent this happening they also bring some additional benefits such as biological and mechanical filtration.
Another area to consider for your own health as well as the health of your aquaculture; is what sort of materials your tanks, pipe work and grow-beds are made from as well as the filter media, grow media, and pumps – in fact anything which is in contact with the water. The Water Regulations Advisory Service (WRAS) publish material properties information and certify pipe work for potable water use including WRAS potable water plastics guide.
We are working on our own guide for safe aquaponics materials as we believe there are further considerations to the simple potable water pipe. For now we suggest using High Density Polyethylene (HDPE) and polypropylene (PP) which are often used in the food industry. Fibreglass is also useable if it is of potable water grade and post cured. Glass and butyl pond liners are also fine to use. It’s best to avoid cheap plastic and PVC as they are harmful to us and to the environment. However, PVC is what the majority of home water pipes are made from, so you might notice we have used PVCu / uPVC in some of our systems.
A good example of non-safe materials in use was when we saw the most stunning homemade grow-bed, ordained with shells and driftwood but it had been constructed using copper sheet – copper is poisonous to fish. This is also something to remember when harvesting rainwater, not many of us have copper roofs now, but those that do need to find another way to harvest rain. You must also ensure you are collecting water from a safe, clean catchment area.
There are several factors to consider when choosing fish.
Is there a suitable feed available for the species, which is sustainably sourced?
Does the species prefer to shoal or be in a community tank?
If the fish are for consumption – what is their growth rate?
Will you breed your own or buy fingerlings?
If your planning to sell your harvest then where and what is the market?
Choose a suitable species for the environment you can afford to maintain, especially in terms of temperature.
Our Fish and shellfish information will help you select suitable species based on their natural requirements and habitats and uses.
If you buy them in then what species will be available within reasonable proximity as it’s going to be a long term relationship with your supplier if your harvesting. Of course if your keeping fish for ornamental reasons then restocking won’t be such an issue and in some respects keeping them as pets simplifies things like treating them when their ill as well as creating a more stable nutrient profile as the fish mature. As mature fish they will also consume less oxygen per body mass than juvenile fish, which means there is more oxygen for the plants and bacteria or potentially a drop in power consumption through air pumps.
If you’re fish tank is 100litres or so you can only add one or two fish at a time, leaving four to six weeks between introductions. With a couple of thousand litres you can clearly add more fish at one go but you’re still only looking at 8 to 10 juvenile fish every couple of months as this will allow for growing on to harvesting without disrupting the systems biology too much.
It’s advisable to quarantine all new aquatic life, it’s simply not worth risking your system as the knock on effect of poor bio-security can be devastating to the ecosystem you’ve cared for and a little impatience can set your system back to zero so be careful.
When your new fish arrive they should be kept in a totally separate mature/cycled tank, this may be where they gradually acclimatise to their new water supply but also to keep an eye on them and make sure all the fish you put in your main aquaponics system are free from disease as far as reasonably possible.
Treat fish or take steps at the very first sign of the first fish being ill, this starts with water testing. Most species of fish pretty active so one of the first signs of a problem is lethargic fish on the bottom of the tank or near the surface of the water. Fish can also go off their food or take on a less colourfull appearance although this is not always a sign of poor health. Health check and treating sick fish.
Removing a fish from water for just a few seconds can have an impact on their immune system.
Avoid handling fish as much as possible, if handling is required there are a few things we can do to alleviate as much stress as possible.
The following are not all necessary for harvesting; these points are for handling live fish with minimum stress caused before returning to a tank.
If you’re going to actually handle the fish then wear gloves to protect their mucus membrane from the oils in your skin. Mucus membrane is the first barrier of protection for the fish and should be disturbed as little as possible.
Instead of using a net to catch and carry the fish, use it to direct the fish into a suitable container that can be carried with water still in it, this saves the fish being removed from water and being damaged by the net. View video demo.
The quality of feed you use determines the potential health and quality of produce your system will grow, it’s the main input of nutrients for the fish and plants so needs to be well considered.
Whichever feed you use it should be of sustainable origin as the vast majority of feeds are unsustainable. Our feed is supplied by Skretting and is of organic, sustainable origin. Aviod using feeds containing krill and other unsustainable fish proteins.
Whilst a great deal of research has been done on fish feeds for aquaculture the more recent studies have largely been to reduce the amount of nutrient waste which pollutes our waterways from fisheries, in aquaponics we need those nutrients. We are developing a range of feeds specifically for use in aquaponics, which is balanced for the fish and plants whilst coming from a sustainable, organic source. Read more.
Many off the shelf feeds are available for the home aquarium to commercial aquaculture. Many are not suitable for aquaponics. Some of the feeds used in aquaculture are developed to reduce nitrate output into our waterways from fisheries discharging water whilst in aquaponics we want those nitrates.
What is worth noting more than any point is that the feed you use must be from a sustainable source. The majority of commercially available feeds come from unsustainable sources and it will take a greater mass of fish from the sea to grow the fish mass in your tank. It is somewhat ironic that a 1kg farmed fish you buy from a supermarket has eaten up to 2kg of fish sourced from our oceans (often krill) which are being pillaged by the corporate world, lets not add to it. Read more.
HOME MADE FEEDS
For species such as Tilapia sustainable feeds are easy to come by, the simplest of which is home grown algae and duck weed, they will also live quite happily on the produce scraps. Trout on the other hand require a high protein diet which can be catered for by breeding black soldier fly larvae (or alternative species native to the UK), insects, worms and hemp seed.