Inside Wall Aquarium Blog

Tips for DIY "Built in fish tanks".

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How hard is it to build a fish tank into your wall?


Quick answer, it’s not hard if you’re handy. Anyone who has experience with drywall and a basic understanding of how a stud wall is built can put a tank into their wall. The only other skill that’s helpful is knowledge of electrical wiring.

First you’re going to cut a hole. You need to know if that’s a load bearing wall or not. If it is you will have to brace it in such a fashion that you transfer the load around the tank. Next you going to finish the stud work and construct a nice flat base for the tank to sit on.

A GFI electrical outlet should be placed in the top corner at this point. If you do not know how to do this you might need to call a friend who does. Then the tank goes in the space, patch up your drywall and trim it out with some wood. Not a hard job if you know what you’re doing.

More detailed instructions:


How awesome is a tank built into your wall?


This is a silly post however, if you are thinking of adding an in wall tank to your house, it’s because they are really cool.  A normal fish tank can look nice and clean but a tank in your wall, one that you see-through between rooms is georgeous!  Guests first response is one of shock and amazement followed by a guess at the cost.  When you tell them that a tank like this costs one-tenth of what they thought and you did all the handywork yourself, they have a new respect for your abilities and think of where they can add one to their home.

Realistic 3d rock wall background


Above is a picture of the background from my tank.  I love the realistic texture of the rocks and the fact that they stick out (some pretty far) into the tank.  There are also caves built into the background that smaller fish can swim through (covered in pic by my giant Oscar).

This background was made with 2″ sheets of white styrafoam insulation, silicone and cement.  First I carved up the styrafoam into rocky shapes and  bonded together with silicone.  I made it in sections so I could put them in the tank after.  Where there are caves I put 2 layers of styrafoam hollowing out the back layer.

Once the styrafoam was sculpted I started to paint/pour cement right on top.  I did 3 layers and I added black and white cement coloring to accent dark and light spots.  I tried to keep it wet with a spray bottle while I was making it so the cement will cure properly.

Then the panels went into the tank.  They were siliconed to the back and I rinsed 3 or 4 times over a week period until my ph levels dropped to a safe level.

It took around 2 weeks to make the background in my spare time and 1 week to rinse but looks awesome, well worth it.  There are a couple spots where the cement has eroded off, I plan on covering these with Java moss.

Java moss, an easy aquatic plant.


Java moss has gained popularity with the aquarium hobbyist however it is difficult to find in a pet store.  It’s surprising because Java moss requires no special lighting, looks amazing and grows in a variety of water conditions.  Shrimp (another recent favorite with hobbyist) and fry love to hide and eat algae off the moss.  It can also be used to make a moss wall instead of a backdrop and it improves your overall water quality.

So, I recently purchased some, not from a pet store but from ebay:

Surprisingly it can be shipped without dying but from the ebayer’s feedback it looks good, can’t wait to put some up!

Running electrical for a tank inside your wall

Obviously your in-wall tank needs to plug in somewhere to run the lights, filter and heater.  First, any outlets around the tank should be GFI (ground fault interrupt).  This is the same type that you have in your washroom.  It will prevent any shock hazards from the water in the tank.

This outlet should be inside your wall opening so you do not see it when you are looking at your tank.  Typically it will be hidden under some trim out of view.  If your opening is tight do not place it in the top center.  It might get in the way of the light (the top corner is preferred).

3 – 4 devices will run off of this outlet so either a double outlet or  power-bar will be required in the end.  Any wire slack can be stapled out of the way.  Do not worry about seeing the wires off to the side, when you look into the aquarium the ends inside the wall will reflect the light inside the tank like a mirror.

In-Wall Aquarium configurations.

There are a few different ways you can configure a built-in wall aquarium.  For clarity purposes I will refer to the 2 sides of the wall as side A and side B.  Let start with the best.  The ultimate in-wall aquarium will have side A and side B finished and trimmed out.  This tank sits flush on both sides of the wall so anyway you look at it, it’s a beautiful clean sharp feature of the house.  No wires can be seen and if you look through the tank you will see fish and another room.  For installs where the aquarium is wider than the wall you can have one or both sides overhanging.  This is not a problem as long as the tank is completely supported underneath with 1 1/2″ of plywood or solid wood screwed into the wall framing.  The tank should be boxed in with trim to finished the look.


If side B is a closet or basement or you just don’t want to see through the tank only side A needs to be finished.  If possible the tank should be accessed from side B.  It will be easier for maintenance than one that is completely sealed in.  A backdrop will block anybody from seeing through the tank.


When you look into a built in aquarium you will not be able to see any wires or wood inside the wall.  The ends inside the wall will reflect like a mirror.

Tips for plumbing an aquarium.

Plumbing your aquarium can save lots of time in the end.

You do not have to run any plumbing to your tank but if you can it will save you lots of maintenance time in the end.

First, if you have access to your pipes, it is a good idea to run both hot and cold lines above your tank.  You need both so you can regulate temperature as you fill the tank.  Pex is the easiest way to add new lines.  I personally use 1/2″ Pex with the rings and crimper.  Crimpers can be expensive but if you look around you should find one for around $50.  I have taps on my hot and cold and then merge them into 1 line attached to a float.  A float will stop your tank from overflowing.  It has saved my hardwood floors more than once.  Get an industrial metal float (not plastic).  I purchased one from ebay.



Next, if possible run a drain under the tank.  This will let your get rid of your waste water and if you make a pan around it, you can clean your filter media there without going to a sink.  I have my canister filter sitting in the pan.  I never have to move it and if it overflows it goes into the drain.  2″ black ABS pipe is easy to work with.  The pieces slide together and bond with solvent in 30 seconds.  You can purchase them anywhere.


Final note, if you run some Pex into your tank that is hooked up to cold water  and another end runs to a drain.  You can easily start your siphon by

  1. Open the water tap which clears out any air.
  2. Close the water tap and open a tap that goes into a drain.

I have my vacuum tube on a quick connect garden hose end that I click onto that Pex in my tank.  I don’t move any tubes for maintenance.  Everything is already there.


I know this may be confusing.  It took me a long time to work it out before I started however the time savings is huge.  I have this plumbed to a 240 gallon tank in my house that is 8′ long and it takes about 30 minutes for me to vacuum the gravel and do a water change (takes 1 hour to fill – on its own).  Cleaning the canister filter takes 15 minutes and I don’t move it which is great because it’s heavy when full of water.

How to clean a Built in Aquarium.

For cleaning this tank you open the trim at top.

Cleaning a fish tank in your wall is basically the same as cleaning a tank outside your wall.  The only difference is that you have less elbow room.  First you will have to gain access to the top of the tank.  This is typically achieved through the top piece of trim.  The trim flips up on invisible hinges or lefts off with Velcro etc…  If the backside of the tank is not finished you can leave it open at the top and access it that way.

Once you have access maintenance proceeds like any other tank.  You will remove around 1/3 the water through a siphon tube.  While you are sucking the water out the waste in the gravel should be removed.  When the correct amount of water removed replace it with tap water and some water conditioner.

The tank does not move and the fish do not come out.