How to choose a tank for your recirculating aquaculture system? A guide from Crawtec
Choosing a tank for recirculating aquaculture systems (RAS) is one of the most important decisions when starting or modernising a fish farm. The tank is the main ‘workspace’ for your aquatic organisms. Its shape, material, depth and location determine not only the comfort of the fish, but also the efficiency of maintenance, energy costs and, ultimately, the profitability of the enterprise. Crawtec shares practical tips to help you choose the right tank for any type of recirculating aquaculture system, regardless of scale.
Fish dictate the requirements for the tank
First of all, the pool should be selected based on the biological needs of the fish. Not all hydrobionts use the same amount of water. All species are divided into two large groups:
Bottom species: the bottom area is important to them, not the volume. These include, for example, the Lensk sturgeon, sterlet, carp, and crayfish.
Pelagic species: volume is important to them, especially vertical volume. Examples include rainbow trout, clarie catfish, and tilapia.
This division is key when choosing both the height and shape of the pool.
Pool shape: there is no ‘universally correct’ shape
Today, manufacturers offer tanks of various shapes: round, square, rectangular, elliptical, and combined. Each has its own advantages:
Round — ideal for creating eddies and circular currents. This is useful for trout or catfish, which prefer moving water. In addition, round pools are self-supporting, so they require less polypropylene thickness, which reduces the cost.
Rectangular pools make rational use of space and are ideal for bottom-dwelling fish. However, in order for them to withstand water pressure, thicker walls or stiffening ribs are required, which can affect the price.
Ellipsoidal pools are a compromise between round and rectangular pools. They are self-supporting and, if necessary, can be better arranged in the room.
Depth, tiering, area — it all depends on biology and purpose
For bottom-dwelling species, depth is not critical. In such cases, it is worth considering multi-tiered structures that allow two, three, or even six levels of pools to be placed on one square metre of floor space. This is especially relevant when breeding crayfish, young sturgeon, or commercial carp in recirculating aquaculture systems.
For pelagic species, depth is critical. But even here, multi-tiered placement is possible — it all depends on competent design, frame strength and ease of maintenance. Crawtec helps customers calculate all loads and choose the optimal solution that will be both durable and economical.
Material and wall thickness: a balance between reliability and cost
Crawtec pools are made of high-quality food-grade polypropylene, which is safe for fish, durable and easy to clean. But wall thickness is not only a question of cost, but also of design features:
In round and elliptical pools, the water pressure is distributed evenly, which allows the use of thinner sheets and, accordingly, savings.
In rectangular structures without stiffening ribs, the polypropylene must be thicker and, therefore, more expensive.
Our team takes into account all the nuances — from hydrostatic pressure to future operating modes — and designs pools with the optimal price/strength ratio.
Ready-made solutions are convenient, but customised ones are always better
Most companies offer only standard tank sizes. But standard solutions are not always ideal for your premises, fish type or farm concept. This can limit productivity and, as a result, your profits.
At Crawtec, we believe that every fish farm is unique, which means that pools must be designed for a specific task.
How to make the right decision?
It doesn't matter what stage you are at:
whether you are just planning construction,
already have an existing building,
or are looking to modernise your existing farm —
the right tanks are the key to the efficiency of your fish farm. And it's much easier to make a choice with the help of our specialists.
Why choose Crawtec?
We manufacture polypropylene pools of any complexity.
We advise on the choice of thickness, shape, depth and tiering.
We provide technical justification for each solution.
We work with both private entrepreneurs and large farms.
We select turnkey pools — from drawings to installation.
Submit your request today and receive advice on the optimal set of pools for your fish farm. Don't waste money — invest wisely.
Crawtec — smart equipment for profitable fish farming.
A little more about ergonomics and maintenance
In addition to fish biology and technical characteristics, ease of operation should also be taken into account. A successful farm is not only about good fish growth rates, but also about convenient work for the staff. What does this mean?
The height of the pool sides should be such that maintenance (cleaning, fish harvesting, condition monitoring) is convenient without the need for additional equipment (ladders, stands, etc.).
In multi-tiered structures, it is important to ensure access to each tier — either through side passages or using special platforms. Crawtec designs modular systems where everything is planned in advance.
The drainage system is another critical element. It must be reliable, leak-proof, easy to use and located at the lowest point of the pool. Crawtec uses proven welded connection solutions that guarantee complete tightness and durability.
Flexibility in approach is the key to efficient production
Modern RAS are not template designs. The market is changing, technologies are evolving, and farmers are becoming more experienced. A successful farm must adapt to new conditions. Crawtec offers flexible solutions:
the ability to quickly repurpose tanks (for example, from fry to market fish);
mobile pools that can be dismantled and moved;
customised polypropylene colours to improve fish visibility, cleanliness control and room design.
In addition, at the customer's request, the pools can be equipped with additional options: siphons, nets, covers, drain trays, fittings, etc.
There is no such thing as a universal tank. But there is a universal approach
We often encounter situations where farmers try to ‘adapt’ their business to a standard tank because it is ‘cheap and available.’ But in practice, such savings often result in:
loss of potential production volume;
difficulties in maintenance;
premature wear and tear of equipment;
or even the death of part of the livestock due to incorrect hydrodynamics.
It is more correct to create equipment for your system, not the other way around. And this is where Crawtec will help you avoid unnecessary compromises. Thanks to our own production, we not only adapt ready-made models, but also create new types of pools from scratch — in accordance with the specifics of your premises, investment volume and biological needs of fish.
Conclusion: choose wisely — win for years to come
Which pool is better? Rectangular or round? Deep or shallow? Ready-made or customised?
There is no single answer. But there is one rule: the right pool is the one that takes everything into account. Fish biology, logistics, hydrodynamics, budget, space and service.
Crawtec combines all these parameters in its projects. We don't just manufacture tanks — we create the basis for your fish farm.
Contact us today, and together we will develop a pool that will serve you for years, helping you to make a profit and develop aquaculture in Ukraine.
