A beautiful fish, diverse in color and size, has great meaning in terms of feng shui. It is possible to raise ornamental fish indoors or outdoors, where there is a clean and fresh water source. Combined with the garden, trees, plus a swimming pool. Certainly, the beauty of the house is greatly enhanced.
Read the article to know how to build a simple cement aquarium at home according to the correct size and standards and safety regulations for living conditions. And not only for Koi fish, this aquarium can completely make an aquarium, raise saltwater marine fish, bettas, guppies, other freshwater fish…
Preparing to build an outdoor cement aquarium
Cement aquariums or cement aquariums are often built outdoors with many different sizes. Depending on the area of the garden to balance the ratio accordingly. Before learning, you need to find out how to make an aquarium with cement , the necessary materials, the construction location, the direction to build the aquarium, whether it is suitable for the age and destiny of the owner. This is very necessary, because not every age is suitable to build an aquarium outside, in front of the house.

If you want to raise a koi pond in a cement pot (cement tank), you need to prepare a detailed plan and plan as follows:
Design and calculate materials
Usually, there will be units specializing in the design and construction of koi tanks for you to contact and help. They will redraw, advise and choose the best option for the family. Based on the needs of the family, actual conditions, financial ability to come up with a solution.
However, in case the family wants to save costs or can’t find a suitable unit, they can also come up with ideas and build their own house. To get a rough idea, it is necessary to answer the following questions:
– What is the shape of the aquarium, round, square, winding, semicircular or rectangular?
– What is the size of the tank? What is the length, width, diameter, depth?
– Where is the direction of the tank to look, is it suitable for the age of the owner, convenient for water supply and drainage?
– The surrounding area is dry or wet, narrow or spacious, can more trees be planted?
– Cement fish tank is leveled or hit the trough, creating a square box shape…
These will be necessary and important questions to help you form the idea, the shape of the tank in your head and outline it outside. Or communicate directly to architects. The details, the more complete, the more accurate and fast the construction process of the Koi fish tank.
Prepare materials to build aquarium with cement
The materials needed to have an outdoor cement aquarium include:
– B5 durability M75 brick
– Yellow sand, cement
– Waterproof material (based on waterproofing method to choose suitable waterproof material)
– Black nylon bag lined with background
– Clay + earth fill the bottom of the tank
– Accessories: PVC pipes, PR water pipes, stacking stones…
– Mesh compartments, pumps, garden aquarium filters, outdoor aquarium water filters…
– Decorative accessories, trees planted in and around the lake to create a more vivid landscape.
The ratio and weight, the specific amount will depend on the size of the tank, how big the fish is to prepare correctly.

Preparing the ground to build the aquarium
– Clean the flat surface, no soil, rocks, gravel or weeds.
– Dig deep into the ground, prepare for the construction of an outdoor aquarium.
– Use lime and some drugs to kill harmful bacteria – mold around before construction. Make sure the environment is clean and there is a source of clean water to supply.
When choosing to make a guppies, koi, goldfish, Ali, discus or betta fish tank…outdoor, it is necessary to pay attention to the cement fish tank that is present inside for carpentry. It is better to paint the aquarium with a black layer of waterproofing. This makes the aquarium look cleaner, transparent, easy to highlight the color of the fish, the color of the moss underneath. Of course, waterproof paint is effective, and the waterproofing time is also much longer.
One note when designing and making outdoor cement fish tanks is that ceramic tiles should not be laid at the base of the aquarium. Ceramic tiles have many colors, more beautiful but do not highlight the color of the fish. Instead, they focus more on the brick pattern, due to the impact of the water, it is easy to cause confusion, too many points of view. Moreover, ceramic tiles make it difficult for moss to grow, losing a good source of natural food for fish.
How to build an outdoor cement fish tank
1. Dig the ground and create the lake bed
Use tools and support equipment such as hoes, shovels, shovels to create lake beds. The depth of the cement fish tank also needs to be calculated, based on the length of the fish and subtracted when the fish grows up. For small fish, the usual depth of the tank is not more than 80cm. This depth is just right to observe and monitor the growth of fish.
Large fish more than 50cm in size, the depth will be greater. Not only for koi , but also for freshwater fish such as snakehead, catfish, eel, seafood tank… Deep lakes create favorable conditions and habitats for fish to grow. There is space to grow and swim.
The capacity of the tank can range from four to several tens of cubic meters depending on the construction site. Particularly, outdoor mini aquariums will have different sizes and standards. The edge of the aquarium should be built about 30cm above the water to prevent the fish from jumping out of the tank or the water spilling out when the fish swim.

2. Create a reverse waterproofing layer for the aquarium
In order to avoid water infiltration from the outside into the ground, through the walls of the tank and then into the water source for fish farming. It is necessary to create a reverse waterproofing layer from the outside in. One of two ways can be used:
– Use nylon to cover the outer layer
This way is chosen more and more popular. The construction time is fast, the construction process is also simpler. First. Cover the ground with a layer of nylon. Then pour a layer of mortar to create a flat surface – this is the buffer for the aquarium.
– Use clay
This method usually has a longer life, but must ensure the source of standard clay. Because otherwise, it is still waterproof, from the inside out and from the outside in. Serious impact on the quality of the work.
Take a small amount of clay to cover the surface of the hole just dug. The thickness is about 3-5cm. If you have a large cement fish tank, you should use more iron to create a frame underneath. At the same time, install the underground water system running according to the design and then pour a layer of concrete to prevent water. Next are the water supply and drainage pipes for the tank.
3. Build a brick aquarium frame
Use M75 bricks to make the tank frame. Create a solid frame for the tank really well, the circuit is full of mortar. Avoid the same circuit as possible, it is not necessary to build a flat like building a house wall.

4. Plastering to create waterproofing
Create a mortar that is smooth enough and capable of preventing water from seeping out of the tank walls completely. Refer to water tank surface waterproofing techniques. For effective waterproofing, the solution can be mixed into the mortar. Plastering in 2 different layers and using a glass mesh to increase bonding and water division.
Finally, apply a bitumen film to create the most thorough waterproof surface.
It is recommended to install a water filter system to ensure a good water environment for fish to grow. Or you can consider building a separate aquarium filter when raising koi or other fish that are highly demanding on the living water environment.
In case the filter is damaged and you want to drain the water, the fish is still alive, so you should see the water collection tube a little higher than the bottom of the lake.
In addition to gas generating devices, it is possible to build a waterfall for the aquarium in the yard to make the tank more beautiful and create a clean environment for the aquarium.
Decorate more rockeries and miniatures to create a truly relaxing space. Miniature ecological garden model. Plant more trees around, create shade, good for the growth of moss. Decorative lighting system to highlight the scene.
5. Decorate the aquarium more lively
Around the aquarium, we can design rock formations to give the aquarium a natural beauty, we can also plant some ornamental plants such as lotuses, guns to create shade for fish in summer days, design catch lights. The eye is also a highlight for the aquarium to be more beautiful. In addition, to have a position to watch fish, it is recommended to design a table and chairs with Japanese style. At that time, we already have a poetic space in the style of Japan already.

How to take care of aquarium built with cement after construction
After construction, the care process is also very important. Thus, the new aquarium can operate efficiently and prolong its life. Need to regularly clean and renovate the outdoor cement aquarium . Handling when the aquarium is mossy, green algae and reverse seepage.
– Treatment of outdoor aquarium moss: Use a dedicated outdoor fish tank moss treatment. Less harmful to fish and surrounding microorganisms.
– Clean the fish tank periodically, do it in the water source. Do not give so much food that the fish will not eat it all. Check the water source regularly, limit the arising diseases.
– To make the water clear, it is necessary to periodically clean, use safe biological products and change the water regularly for fish.
– About 50% of the water should be changed within 3 weeks, at the same time remove the leftover food, residue after the fish eat. This is the easiest and most effective way. Use a racket to pick up leaves and rotten leaves from the surrounding trees and fall into the lake.
– On days when the weather is too hot, it is possible to add a sunscreen net, a roof to avoid harsh sunlight from the sun.
– When it rains heavily, it is necessary to have a tarpaulin or net to prevent fish from drifting out with the water.

The aquarium is well cared for with clean water quality
How to deal with waterproofing when building an aquarium with cement concrete
If you are not a professional, highly skilled worker, it is understandable that a cement concrete aquarium is permeable. A leaky fish tank doesn’t just cause an annoying water leak. Over time, it also affects the health of the fish.
To treat waterproofing when building an aquarium with cement , you can use one of the following methods:
Waterproofing with emulsion film
This is an extremely good waterproof material. Both good waterproof and good insulation. Suitable for weather and climate in Vietnam through high elasticity.
First, proceed to clean the area to be waterproofed. Removes debris, mortar, excess concrete during construction, garbage, dirt, sediment…
Next, plaster a layer of cement mortar, about 1-2cm thick. Wait for the cement mortar to dry, mix pure chemicals with 20% water to dilute, spray evenly on the bottom surface and walls of the aquarium.
Wait for the primer to dry and then apply 2-3 coats of paint, pure emulsion on top. Note that it is necessary to let the old layer dry before continuing to the next layer. Finally just pump water in to test the effect.

Waterproof with self-adhesive membrane
Create a primer for construction. Polyprime solvent-based bituminous primers can normally be used. Using a roller, apply a thin layer with the volume from 0.3-0.4 liters/m2. Wait for it to dry and proceed to the next step.
After the liner has completely dried, spread the roll of self-adhesive film. The length of the membrane matches the length of the construction area. Cut the adhesive film to the desired size with the required width.
Peel off the silicone cover and apply the film directly to the primed surface. Requires a minimum overlapping area of 5cm. Use a roller to smooth your hand from the center to the edges to avoid air accumulation.
Apply cement + sand mixture on top to protect the self-adhesive film just pasted. Finally, the project acceptance test.
These are two ways to treat waterproofing when building an outdoor cement aquarium that is very simple and effective. Besides, there are still many other types of waterproof paint sold outside on the market with the same method. Homeowners can consult or ask for the advice of architects.