Inside Wall Aquarium Blog

Tips for DIY "Built in fish tanks".

Home » 2015 » March

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.