Aquaponics tanks are really cool projects. If you’re looking for a total sense of satisfaction that comes from creating something awesome, then you should seriously consider trying this.
An aquaponics fish tank is a system that combines underwater plants, animals, and helpful bacteria. For example, live aquatic plants could be placed with snails, shrimp, crayfish, and (of course) fish. The objective with one of these systems is to create a symbiotic environment, where the individual elements take care of each other.
The really cool thing with aquaponics is that you can grow your own food. This can be handy to have on your resume if you ever decide to volunteer for a Mars colonization program. Aside from that, a lot of people find this to be really satisfying.
To be clear: this article is focusing on aquaponics as a hobby, not a commercial operation designed to produce large quantities of food to be sold or support a family. Although the principles are the same, that’s a whole other animal.
In this article we’ll go over what you’d be getting yourself into, what it takes to pull this off successfully, as well as some tips and tricks so you don’t end up with a big tank of dead fish and veggie soup.
How Do I Get Started With Aquaponics?
The startup phase is pretty intense, to be honest. This won’t be a one day build by any means.
Before you actually get started, you really need to ask yourself if you’re up for the job. I’m not going to get into a “responsibility of pet ownership” speech (hopefully you’ve already thought of that), but just the work alone isn’t for people with a casual interest. Also, as you read through this article, you’ll notice that there are a lot of things that can go wrong. Just make sure that you have a good area for this and that you’re up for the project.
There are a few things that you need before you get started.
Here’s a list:
- One or more fish tanks
- One or more grow beds
- Grow bed stands
- A sump tank (optional)
- Pipes and fittings for plumbing
- Stand pipes or siphons
- An appropriately sized water pump
- Air stones, airlines and an aerator
- Grow lights (if needed)
- Heating elements
- Grow media
- Filtration system
- Timers and controllers
- Water quality test kits
- pH adjusters
- Cycling kit
- Monitoring equipment
- Fish food
- Gardening supplies
- Seed starting supplies
- Pest management supplies
Beyond that, here are a few considerations when it comes to where you’re going to set up.
For example, do you have an area large enough? Not all systems are huge, but they’re no betta fish teacup, either (btw, please don’t put your betta in a teacup).
Can the area get wet? It doesn’t matter how careful you are, you will have spills. What kind of flooring do you have? Don’t do this with carpet flooring, you’ll have a moldy disaster. Ceramic tile or concrete with nearby drainage is a good idea.
Is your area affected by blackouts or brownouts? Do you have a backup so your system doesn’t die when your pump stops?
Other challenges regarding aquaponics:
- It’s hard to travel – these things require regular monitoring.
- You really need to be a half decent DIYer, unless you’re willing to pay for someone to build the system for you.
- It can take a while to figure out a good balance for your own system.
Assuming that you’re up for the task, let’s get to know the system a little better.
What Do Fish Do in Aquaponics?
The whole idea is that we’re creating a symbiotic environment. The fish create detritus. This nourishes the plants and lets the whole system thrive.
In case you’re wondering, detritus is fish poop.
Plants love it. It’s full of minerals and goodies that plants love. Plus, how cool is it to grow a salad that’s been cultivated with fish poop?
Besides that, fish look cool. A water tank of vegetables isn’t nearly as fun.
Do You Have to Feed Fish in Aquaponics?
If you want your fish to stay alive, it’s a good idea to feed them.
You’re going to need to give your fish something to eat; they won’t just be able to survive of what you grow in the system.
That said, you can make what’s called a side stream and feed the fish partially on what’s grown here. This can be tricky, though, and is more so appropriate for advanced users only. The reason is that this stuff can usually clog the filters and cause a lot of problems if you’re not careful. These will also decompose faster and can affect water quality.
If you’re going to use these plants to feed your fish, it’s actually best to remove them and dry them out fully before reintroducing them as food. This will basically just make it easier to control and reduce the amount of decomposing vegetable matter in the tank.
Beyond this, if you really want to go the DIY route, you can grow your own worms or insects for fish food. There are a lot of kinds out there that are actually pretty easy to cultivate, such as earth worms or blackworms.
Ultimately, though, what you feed your fish needs to be well thought out. Often, simple fish flakes won’t bring the best results. Fish need a varied diet that includes protein, fats, and vitamins in order to really thrive. There are many great solutions on the market in the form of well-balanced pellet food. This is by far the most common route of aquaponics enthusiasts.
Another key factor that most overlook is that you’re not only feeding the fish in these systems; what they eat also feeds the plants.
In other words, don’t underestimate the need for a well thought out food plan.
Aquaponics Fish Tank Design
There are a few key design choices that can either make your system doable for a beginner (relatively speaking) or that will make you tuck your tail and run for the hills. Assuming your beginner, here are some tips that will make your life a lot easier.
There are three different types of aquaponic systems: Deep Water Culture (DWC), Nutrient Film Technique (NFT), and media-based.
DWC and NFT are expensive and challenging. These are more so common in hydroponics, and intended for more commercial use.
Media-based is a much simpler and more economical setup. There are less parts to buy and maintain. Also, media-based takes care of all three elements of filtering: mechanical (removes solids, mineralization (breaks down solids) and biofiltration.
A media bed is also a system that provides better support for plants. It more closely imitates traditional gardening, and your plants will love you for it.
A Simple Flood-and-Drain System
There’s no need to make this more complicated than it needs to be if you’re just starting. Flood-and-drain systems work great and they’re simple to set up.
Here’s basically how they work:
The fish are at the bottom in a tank. The plants are in a tank on the top. A water pump brings the water up into the top tank. The plants feast on the detritus to their heart’s content. They also filter the water. The water drains back into the tank. Letting the water drop back in like a fountain also aerates the water, which makes the fish happy.
This system is also compact and easy to maintain.
Make Sure Everything’s Supported
Water is pretty heavy stuff. It’s important that the supporting structure can handle the weight.
Try to work out how much weight the stands will be supporting. Water weighs 8.34 pounds per gallon. That means that a bathtub-sized tank (80 gallons) will weigh about 650 pounds. If you have one for your fish and one for your plants, that’s a 1300 pound system!
Here’s a tip before you assemble your tanks. Get a few people to stand on the structure to see how sturdy it is. Just roughly match the weight of the people to how much the filled tank will weigh.
Pro Tip: Don’t use women for this. They don’t like it when guys calculate their weight. (source: my wife)
Aquaponics Fish Tank Setup
Setting up your tank isn’t really all that complicated if you’re making a simple media-based flood-and drain-system.
Start off with the construction. Build a platform that can support the plant tank. You might also want a low platform that will raise the fish tank slightly.
Once that’s done, put the tanks in place. Start plumbing.
For the plumbing, you’re just going to run pipe from your pump up to the plant tank. Use valves to allow you to control flow rates. Then make a manifold that will be set at the bottom of the plant tank, under the media. Drill holes along the manifold so water can drain out and back into the tank. Then plumb the drain to return the filtered water to the fish tank. Keep enough of a water drop between the plants and the fish so that the water gets aerated; this just makes for a simpler system.
Add the media in the plant tank. Peat moss or pea gravel work great.
Now fill the tank and turn on the pump. Play around with the valve to get that sweet spot where everything is flowing smoothly.
Check the pH levels in your tank. Adjust as needed and let the system run overnight so everything has a chance to balance and settle. This will also allow the chlorine to dissipate.
Now you can start adding your fish. Do it very slowly (like over the course of several days) so your bacterial colony in the grow bed can start to build up. This is an important step, or else the contaminants won’t be broken down and your fish could all die.
Also expect that you’ll probably need to make almost daily water changes for the first bit while your system is starting up. Otherwise, ammonia will build up to toxic levels and kill your fish.
4 weeks later, you should be ready to insert your plants. Do it slowly so the balance isn’t knocked out of whack. You can choose to either put in the seeds or plant seedlings that have already sprouted. Planting seedlings will get you up and running faster overall.
Aquaponics Cycling Without Fish
If you want your system running a bit faster, you can change around those steps a bit. “Cycling” is your startup phase, where you’re trying to get everything balanced right. You can do your cycling without fish and have a finished system several weeks earlier.
Basically, all you need to do is get the ammonia levels up. Ammonia is created from the fish gills as they “breathe”. This is what feeds the bacteria colony that needs to grow in your system. They’ll naturally show up once there’s a food source for them.
These bacteria break down the harmful nitrites into harmless nitrates. The nitrates are what your plants love.
If you add the fish first, the ammonia levels will build up and become toxic to the fish. That’s why you need to do so many water changes for the first few weeks until the bacteria colony sets up shop. Otherwise, the fish all go belly up.
The real advantage to fishless cycling is that you can just pour in a much higher concentration of ammonia to kickstart the bacteria. Use 100% liquid ammonia (no additives or perfumes) that’s at a concentration of 5-10% by weight.
Another route that some people decide to take is to pee in the water. This is nasty, but it does technically work. Urine generates ammonia. This has a lot of cons though – there’s a risk of introducing harmful bacteria in the system, and the ammonia level is harder to control since it takes a while for urine to convert. So while it is technically possible, it’s probably best left for the Mars missions.
Edible Aquaponics Fish Tank Plants
The fish and plants need to be able to maintain a good balance. It’s best if you pick plants that thrive in the same pH levels and ideal temperature that your fish need.
Here’s a list of great options for your setup:
Hardy aquaponics plants for any standard pH level and temperature:
- Pak choi
- Swiss chard
- Mint (especially practical for mojito lovers)
More demanding aquaponics plants:
Extremely demanding aquaponics plants:
- Beets (Dwight Schrute could probably pull this off)
- Micro greens
I’d really recommend taking your time to plan out your choice of plants vs fish carefully. You’re setting up a symbiotic environment, so everyone needs to get along.
Since every subspecies of plant is slightly different, I’d recommend looking up the exact requirements for the type of plant you’re wanting to put in. Not all tomatoes and kale are the same, so do your homework!
House Plants for Aquaponics
If you’re just wanting something pretty to decorate your system, there are a lot of house plants that do very well with aquaponics.
Here’s a list of some popular options:
- Peace lilies
- Snake plants
- Spider plants
The really cool thing with aquaponics is that the plants are given a huge amount of nutrients, usually far more than they’d get from soil. This makes them really thrive and grow substantially fast. You’ll also notice that the flowers will be a lot brighter and fully with all these extra nutrients.
Ultimately, you can really customize your system based on what you want. If you want a setup that pumps out salad, that’s totally achievable. If you want something decorative, with goldfish, koi and lush flowers, this can totally be a highlight of your garden.
Basic Aquaponics Setup
Really, you don’t have to make your system too complicated. You can make a scaled-down version that’s low maintenance and not too hard to build.
If you do a media-based flood-and-drain system, you can use smaller tanks and still have a really satisfying setup. I like to use these for kitchen herbs and small flowers; these little setups can be really satisfying. There’s nothing better than garnishing a plate with herbs that you harvest from a little ecosystem that you built yourself.
Overall, the system will take several weeks to gradually build up and balance, but this is great for weekend projects!
Beyond that, aquaponics are great conversation pieces! I can guarantee you that everyone that comes into your home will have a ton of questions about how the system works, and you’ll have significantly more street cred.