Building An In-Wall Aquarium – What To Look Out For

Constructing a marine aquarium system is very enjoyable and exciting, with all the research into different types of equipment that will be needed following the decision on what type of system to have – fish only, corals only, or mixed.

As has been mentioned before in other texts the first consideration is, unremarkably, knowing the space that is available to place the aquarium in. There is hardly an occasion when an aquarium cannot go somewhere suitable, as size and shape can be chosen from the commercial products available.

There is another alternative possibly available and that is to have an in-wall aquarium. This is where the aquarium is placed in a specially sized hole in the wall, with the front viewing glass of the aquarium in line with the wall. This alternative is attractive to those who find space to be at a premium and also those who want to have the entire aquarium out of sight apart from the contents. If this is done successfully the end product is a living picture.

The requirements of the actual livestock support system don’t alter. There is still a need of course for bio-filtration, heaters, lights etc. There is also a need to have an electrical output within the cupboard or other space that is to be used behind the wall. In addition, consider the strength of the floor. This consideration is required before placing an aquarium anywhere. The floor must be able to take the weight of the full and stocked aquarium and sump.

It is necessary to give consideration to one or two other matters. There is going to be a hole in the wall. Large or small, this will be only slightly larger than the aquarium itself. However, space has to be allowed vertically for the support under the aquarium, this will extend to the front of the aquarium and so the height of the hole will increase by the thickness of the support. If a ‘soft’ cushion, such as polystyrene, is required then the height of the hole will increase by that thickness as well. Polystyrene is a good insulator so the aquarist may wish to enclose the aquarium sides and back with polystyrene. If so, the width of the hole needs to be increased by twice the thickness of the insulator. There are no worries about ugliness, as a ‘picture frame’ can be placed around all four edges of the front of the aquarium when installation is complete.

Once the position and size of the hole are known, it is necessary to consider the wall itself. Is it brick or block, or a timber framed plastered dividing wall? Whatever it is, consideration absolutely must be given to the consequences of creating the hole. Is the wall load bearing? Will additional supports be required to maintain strength and stability when the hole is created? In a brick wall, a lintel could need to be put in place by removing a row of bricks before the main hole is created. In a timber framed wall, additional timbers may be required above and alongside the hole before cutting commences. If there are any doubts at all, it is best to get experienced advice before any action commences. The construction process is pleasurable, but not if constructional stability problems commence at the start.

Ok, so all is well, and the hole is cut. If the edges are a little ragged this doesn’t matter as they are to be covered at the end by the ‘picture frame’ already mentioned. A check should be made though that the sides are vertical and the bottom horizontal or the seawater in the aquarium could give the game away. The next job is to make sure that an adequate support for the aquarium is made. This has already been taken into account when the hole size was being considered. The support will be in a cupboard or small room that is not accessed for living purposes, meaning that the support need not be a work of art. However, the support must be adequate; an aquarium full of rocks, sand and seawater is very heavy.

When constructing the support consider the possibility of a sump. A sump is recommended as equipment such as heaters and skimmer can be placed in it removing their unnatural presence from the display aquarium. A sump also increases the total gallonage of the system which is good for seawater quality, and on the same basis additional filtration such as a deep sand bed (DSB) can be placed in it. As the sump will not be seen it can be open to view in the cupboard/room and stand under or alongside the display aquarium. There needs to be adequate maneuvering space for the aquarist to carry out maintenance.

The aquarist will have already decided what type of system it is to be. The lighting needs to be considered.

If fish only, then generally two fluorescent tubes running down the length of the aquarium will suffice. The fish need to see and be seen, there isn’t any demand for light other than that. The light spectrum can be chosen to enhance the colours of the fish – one marine blue and one marine white are often used. This enables a ‘dawn/dusk’ lighting sequence to be used as well.

If corals are to be included in a coral only or corals and fish system, then the lighting needs more consideration. This is for two reasons, first the corals special demands for light and second because of heat generation. Consideration of coral lighting demands is covered well in other texts and will not be repeated here.

If fluorescent lighting is to be used such as T5’s, there will be more heat produced. As the lights are in an enclosed space (the small room or cupboard), it is possible that the air will be heated to a sufficient extent that the seawater temperature is affected. This is good as far as electricity consumption is concerned as the heaters will be on less. However, excessively fluctuating temperature is bad, and even worse is a temperature climbing towards 84 deg F or higher. This is quite possible under some circumstances. Though there is usually some small temperature variation, the average temperature needs to remain at the design point.

It may be that the aquarist is to keep hard corals such as SPS (small polyp stony) in the aquarium. Though it is possible with a shallow aquarium to use fluorescent T5’s to reasonable effect, normal aquarium sizes are more likely to require metal halides. Metal halide bulbs emit intense light, but also unfortunately heat up the seawater. Though this is again advantageous in that the heaters are required less, the seawater is usually heated excessively, causing the aquarist to seek means, such as a chiller or electric fans, to keep it cooler. This is in a normal ‘in the room’ situation. In an enclosed cupboard or small room, the seawater is quite likely to heat up even further, as not only is heat being put into the seawater directly, the air surrounding the aquarium is also going to become very warm. This means that the aquarist cannot use electric fans for cooling, but would have to resort to a chiller, not the cheapest device to purchase or run.

So the aquarist needs to consider methods of cooling the seawater if metal halide lighting or possibly multiple fluorescent T5’s are to be used. By all means purchase a chiller if the cost of purchase and running is not a problem. In most cases there are better alternatives.

The room or cupboard that houses the aquarium needs to be looked at. Is there an outside wall to the room/cupboard? Is there a means of getting to one if not?

Once this has been answered the aquarist can easily prepare for any overheating problem. The best solution of all is to use two wall-mounted electric fans. These fans are the ones that sit in or on a hole through the outside wall (these are not big, usually have no constructional stability dangers, and do not present any cosmetic ugliness). If the outside wall is one of those in the cupboard/room, no problem – if not, then flexible ducting can be run to the nearest outside wall from inside the aquarium area. These can go under the floor or where convenient. The restriction is that the fans usually have a limit to how far they can blow or suck the air. This needs to be checked and, if necessary because the ducting is over-long, more powerful fans obtained.

It is best to have one fan that sucks air in at one end of the area and one that blows it out at the other, creating a flow of cool air. It is possible to purchase a unit that has a probe within the seawater – if it climbs to a preset temperature the fans turn on automatically. Keeping the air cool in the aquarium area is good and worthwhile, and will help control seawater temperature. However, lighting systems, particularly metal halide, could heat the seawater excessively despite the cool surrounding air. In this case, air blown across the seawater surface will cool it, and of course the aquarist has made this cool air available.

Depending on the lighting system and the aquarist’s geographical area, it could be found that fan assistance as described is not required at all, or only one fan is needed. Situations vary.

Once the major construction is done, everything else is the same as with any other aquarium.

I have had one ‘in the wall’ aquarium. It was successful and eye-catching, containing a soft coral reef and two fish, a flame angel and a royal gramma. It was closed down eventually purely because the aquarium was small and there wasn’t enough room to place a bigger one. I obtained a bigger one and put it in the living room, closing the hole to make it a normal wall again.

There weren’t any problems in maintenance, except for cleaning the algae off the front glass. To be honest this wasn’t a problem really, it was just that I had to keep going out of the cupboard to stand in front of the aquarium to note if any algae had been missed. When more stubborn algae needed to be removed and several checks had to be made it was a little irritating.

Then my wife, helpful as ever, started to stand in front of the aquarium and give directional instructions. It might sound excessive but actually turned out to be fun.

  1. No reason to build an in wall aquarium…unless you have a budget of $2000 or more. All good points and its expensive if you do it wrong.

    Just bought a wall mounted fish tank from – much easier.

  2. Not true. I have a 20 gallon in wall aquarium I bought from and the entire project cost me under $600 and only took a couple afternoons.

  3. Wall-in aquarium looks unique and fabulous inside the homes. Ensure fishes’ safety with proper care and aquarium maintenance. Many thanks.

  4. I have a 55 gal aquarium in our game room and I also have a 30 gal in my bedroom and everyone that sees them love them. My husband and I are planning to install our third tank, a 75 gal in our kitchen and livingroom wall. We will set it up so you can see threw the kitchen to the livingroom. This shoud open up the space a little and incorperate a nice living picture. I can’t wait until it’s all done. We just love our tanks!! It really doesn’t take that much to put in a wall tank just alot of planning. The expense of having a unique living picture is worth it.

  5. Hello Shannon. It sounds as if the marine bug has certainly bitten. It’s a wonderful, entertaining and educational hobby. Enjoy!

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