Indoor Fish Tank Aquaponics: Complete How-To Guide

Getting started with aquaponics is as easy as setting up a personalized grow system from an ordinary fish tank.

We’ve done it before, as have countless others with little to no experience, and so can you!

To get started, simply gather up a few basic supplies (listed below) and follow the easy instructions presented here in this guide!

Supply List

Building Your Fish Tank Aquaponics System

1. Set Up Your Fish Tank

The first step is setting up a fish tank. You may use a standard 10, 20, or 40-gallon tank for fish, or opt for something more affordable.

Many DIY aquaponic systems are made with food-grade containers like totes or large rain barrels. The choice is yours.

Once you decide on what type of tank to use, go about setting it up just like a normal fish tank. That means you need to add water, dechlorinate it, and give it a month or so before adding fish if you aren’t planning on constant aerating. Otherwise, your air pump and air stone will clean the water up to within a few days to a week.

During this step, make sure that you install a submersible water pump (like this 50gph model) in the tank and air pump (this works with 20-100 gal tanks) outside of the tank.

You also need to connect an air stone (here’s a great deal on a 10-pack) to the air pump and place it at the bottom of the tank. That way, once the media growing bed is installed, the water and air can recirculate through the system properly.

2. Create A Media Bed

Building the media bed is the second step and is a crucial one at that. The media bed, also known as a grow bed or flood table, is where the plants will grow.

Common DIY media beds are typically made out of shallow totes (like this), plastic trays or bus bins, or even wood lined with heavy-duty plastic sheets. Make sure that your grow bed has the same (or very close) volume as your fish tank.

When you’ve decided what to use for the grow bed, you need to create a support system for it. Shelving or even a table will work. Keep in mind that the bed will be much heavier once a growing medium and plants are added, not to mention water.

The grow bed works best positioned just above the fish tank, but it can also be located to the side of the tank if supporting its weight is an issue. However, in this case, you may need an additional water pump.

Once your bed is in position, it’s time to add the bulkheads.

Do so by drilling out holes and inserting the bulkheads. Most of the time they come with gaskets that create a water-tight seal. If yours don’t have seals, use rubber cement or a universal sealer to make sure there are no leaks.

Now, add your preferred growing medium to the bed and it’s time to move on!

3. Connect Pipes from Water Pump to Bulkheads

Next is a slightly intimidating step, but actually one of the easiest parts of the whole project. Simply connect your PVC pipe to the bulkhead you installed on the bottom of the media bed and position it down into the fish tank. 

Also, connect a proper length of tubing to the outlet on the water pump, and run it to the top of the media bed. Once connected, the water pump will send water to the grow bed, and after soaking plant roots, it will drain out through the PVC pipes and return to the fish tank.

4. Add Water to the System

The next step, after your fish tank and media bed are set up, is adding water if you didn’t do so when you initially set up the tank. If you did add water already, it’s time to change it out with fresh water. That way any residue or contaminants left over from constructing the system are removed.

5. Add Fish to the System

Steps four and five are technically interchangeable, but we suggest adding the fish first. Likewise, if you are experienced in building a fish tank aquaponics system, you may have already added fish while setting up the tank itself.

At any rate, for this step, double-check your water’s pH and EC levels with a meter or test strips. This is one of the best pH/EC test meters around.

If they aren’t balanced enough for the type of fish you will use, use liquid pH and EC adjusters to fix the issue.

Once you’re sure your water is ready, carefully add the fish into their new home (read my article on Best Aquaponic Fish)

You may want to give them a few days, or even weeks, to adjust to their environment before moving on to the next step (though it is not exactly necessary).

6. Add Plants to the System

Once everything else is done and you’ve ensured there are no leaks, as well as testing pH and EC levels, it’s time to add the plants.

Depending on how you set up your media bed, you may add plants to individual netted pots sunk into the growing media, or set the roots of each plant into the bed and cover them with a loose growing medium so that they are probably anchored.

Make sure that you rinse all traces of soil from plant roots if you are transplanting plants started in soil. Plants started in growing sponges or hydroponic seed starters can be directly transferred into the bed.

Either way that you set your plants up, the system will function the same way. Water pumped from the tank, along with nutrients provided by the fish, and air provided by the air stone, will now circulate through the growing bed, feed the plants, and drain back into the fish tank.

Fish Tank Aquaponics Routine Maintenance

Operating your new aquaponic system is fun and exciting, however, it also requires a bit of routine maintenance:

  • Feed fish daily and check for dead fish
  • Avoid overfeeding the fish
  • Check plants for pests and diseases often
  • Keep a 1:1 (fish to plant) ratio
  • Keep an eye on water temperatures daily
  • Regularly balance pH and EC levels as needed
  • Check for leaks and malfunctioning equipment
  • Change water and clean filters or air stones

Common Problems & Solutions

Unstable Water Temperatures 

When water levels rise to temperatures that are unbearable for either fish or plants, you have a serious problem on your hands. That said, it is one of the most common problems of all when it comes to fish tank aquaponics. If left unchecked, your fish, plants, or both will begin rapidly dying. 

Solution

There are several easy solutions for unstable water temperatures. The first is to simply keep an eye on water temperatures daily. That way you know exactly how the situation is.

The most basic way for fixing the situation is simple: top off the tank with cool water or add a fish-friendly water coolant. You could also add a water chiller coil to the setup that will regulate the temperatures.

In addition, you can use one of the following methods for preventing high water temperatures:

  • Paint your water tank(s) with a solid color to keep excess light out (inside of outside)
  • Bury the main water tank in the ground (if outdoors)
  • Keep a fan blowing directly on the system to disburse hot air (inside or outside)
  • Install a swamp cooler beside the system (if inside)
  • Use sun umbrellas to shade the system during the hottest part of the days (if outside)

Unbalanced pH Levels

An extremely common problem experienced by newbies and seasoned professionals alike, unbalanced pH levels is a sure way to end up with dead fish and plants. Keep in mind that different fish, and plants, each have preferred pH levels.

There is no one-size-fits-all in regards to pH level.

Solution

The first step to solving an imbalance in pH levels is knowing what pH levels should be for your fish and plants in the first place. Next, using proper fish for the sort of crops you’re growing goes a long way in naturally maintaining the correct pH balance.

That said, when pH levels are out of whack, take immediate action to solve the issue by adding liquid pH adjusters (the kit I use) as needed. 

Too Many Fish in the Tank

Having too many fish in your tank is another common issue. Too many fish typically leads to one of two things; less oxygen due to clogged air stones and filters, or higher levels of nutrients than necessary.

Solution

The easiest solution for this problem is removing fish. You can sell them, eat them, or keep them in a separate tank. A general rule of thumb is to keep one fish in your tank for each plant in your system. That’s usually about one fish per 5 gallons of water.

Alternative Methods for Indoor Aquaponic Setups

The DIY tutorial above is just one of many methods for building your own indoor aquaponics setup. 

A couple of the best alternative methods include:

  • NFT Aquaponics. This creative form of indoor aquaponics utilizes grow pipes that are constantly flowing with a very thin layer of water and nutrients that plants absorb as needed.
  • Ebb and Flow. Similar to the layout in the tutorial we shared above, the main difference is that indoor ebb and flow aquaponics use multiple grow pipes that are flooded and drained rather than a large media-filled grow bed.

Mini Aquaponic Kits

If you’re not ready to build your own fish tank system, there are a few great options available that come pre-made and require minimal setup.

I’ve included some of my favorites for you below.

AquaSprouts Garden

The AquaSprouts Garden not only houses live fish, but it also looks great and grows plants as well. The hybrid aquarium and aquaponic system looks attractive as an alternative to furniture or fireplaces in your living room. 

The system is easy to set up, fits on standard aquariums (like the one you may already have), and is great for growing flowers, herbs, and vegetables. Further, it is a great teaching tool for classrooms and the home alike.

Check Price On Amazon

Pros

  • Completely self-sustaining
  • Fits on standard 10-gallon aquariums
  • Works for growing vegetables, herbs, flowers, and houseplants
  • Allows for all year indoor gardening

Cons

  • Takes up more space than ordinary 10-gallon tanks

Kingro 5-in-One Aquaponic Ecosystem

This 5-in-1 Aquaponic Ecosystem by Kingro makes a great-looking centerpiece in any setting, be it the home, office, or classroom. The system is easy to set up and use as well as to maintain. It practically takes care of itself once installed with plants and fish.

This aquaponics ecosystem’s compact design makes it affordable as well. Simply set it up in your home, add water, fish, and plants, and sit back and enjoy the show. You can even use it to supplement herbs for the kitchen all year long.

Check Price On Amazon

Pros

  • Grows all kinds of plants
  • Very aesthetically pleasing
  • Great for pet fish
  • Supports up to 20 plants
  • Built-in LED light

Cons

  • Doesn’t support large vegetable varieties

Back to the Roots Water Garden

Another great alternative to building your own indoor aquaponics system, or adding another potted plant to your home, is the Back to the Roots Water Garden. Easy to use, and guaranteed to work or your money back, it is also an excellent alternative to a standard goldfish or tetra tank.

The design is simple but sleek and brightens up your mood, whether it be in your bedroom, kitchen, living room, or elsewhere. It also makes a great classroom or family project for educational purposes.

Pros

  • Easy to set up and use
  • Perfect for growing microgreens
  • Sleek and simple design
  • 100-percent money-back guarantee
  • Barely takes up any space

Cons

  • Holds less water than similar products
  • Doesn’t grow large plants

A Final Word About Fish Tank Aquaponics

Once your fish tank aquaponics system is complete, you should be growing and harvesting both fish and plants with extremely little effort on your part.

From start to finish, you can build one of these systems in a single day. But, to properly prepare the water, and the fish, as well as start plants, it’ll take around a month to really get up and going.

If everything is done correctly, you’ll notice happy and healthy fish and plants. On the other hand, if your plants are wilting, and fish are turning up dead, there’s a major issue that needs to be resolved.