A Complete Guide to Aquarium Sizes — From 25L to 300L

Aquarium keeping is more than just adding water, fish and decorations to a glass box. The size of your tank will influence almost every decision you make: which fish you can keep, what equipment you need, how often you maintain it, and even how stable the water parameters will be. In this guide, we will walk through the most popular aquarium sizes from 25L up to 300L and help you choose the best option for your home, your budget and your level of experience. MB Store provides a wide range of aquariums and accessories, so you can easily turn theory into a thriving underwater reality.

How Aquarium Size Affects Your Aquascape and Fish

The first and most important rule of fishkeeping is simple: water volume equals stability. A larger volume of water is less prone to rapid changes in temperature, pH and other crucial parameters. In a small aquarium, even a tiny mistake, such as overfeeding or skipping a water change, can quickly lead to ammonia spikes or oxygen shortages. In larger tanks, the same mistake is easier to correct before it harms your fish.

Another factor is the biological filtration capacity. Beneficial bacteria that break down harmful substances live on filter media, substrate, decorations and glass surfaces. The more space available, the more bacteria can settle and process waste. This is why overcrowding is particularly risky in smaller tanks; there is simply less room for colonies to develop. When you choose a tank size, you are also choosing how much biological support your ecosystem can handle.

From a creative perspective, tank size determines what kind of layout you can design. A 25L nano tank can host a beautiful, minimalist shrimp scape, but you will be limited in terms of plant species, hardscape and fish selection. Medium aquariums in the 60–120L range already allow complex compositions with rocks, wood and lush plantings. Once you go beyond 200L, you can create expansive, aquascaping scenes with distinct zones, shoals of fish and impressive centerpieces that become a focal point in your room.

MB Store offers aquariums across this entire range, along with matching filters, heaters, lighting systems and substrates. This makes it easier to plan a complete setup tailored to the dimensions you choose. Rather than adapting equipment to a random tank, you can design the aquarium as a coherent system from the start, which improves both aesthetics and animal welfare.

Choosing Between 25L and 60L: Nano and Small Aquariums

Small aquariums (25–60L) are popular because they fit easily on desks, shelves and small cabinets. They seem simple, but they actually demand discipline and precision. In such limited volumes, fish selection must be very careful. Often, the best choice is to keep shrimp, snails, tiny schooling fish or a single betta rather than trying to build a mixed community. Their low bioload and small adult size match the restricted capacity of the tank.

In a 25L nano tank, every piece of equipment must be compact yet efficient. You will typically need a small internal or hang-on-back filter, a heater adapted to the volume, and lighting strong enough for low to medium-light plants. MB Store supplies ready-made nano tanks and sets that include filter and lamp, which simplifies the selection process for beginners. Careful planting with mosses, small ferns and foreground plants will help maintain water quality by absorbing nutrients and providing hiding places.

Moving up to 40–60L opens more possibilities. You can create a small community of microrasboras, endlers or dwarf Corydoras, provided you respect the stocking limits. The rule of thumb is to research each species’ adult size, social needs and territorial behaviour before purchase. Overcrowding leads to stress and disease, especially in smaller environments. Adequate filtration and regular partial water changes (typically 25–30% per week) become non-negotiable.

One advantage of these smaller setups is cost: substrates, decorations and plants are needed in smaller amounts, so you can invest in high-quality products without stretching your budget. MB Store offers a wide range of plant substrates, fertilizers and compact LED lights designed specifically for nano and small aquariums. When chosen well, such equipment turns a modest volume into a stable and vibrant biotope that looks far more expensive than it actually is.

Medium Aquariums 80–150L: The Most Versatile Size Range

Medium-sized tanks between 80L and 150L are often considered the sweet spot for both beginners and experienced aquarists. They are large enough to provide stable water conditions, yet compact enough to fit into most living rooms or offices. At this size, you can start thinking in terms of zones: foreground, midground and background planting, as well as swimming areas for different species.

Stocking options are significantly broader. A 100–120L aquarium can house a harmonious community of small tetras, rasboras, livebearers and peaceful bottom dwellers like Corydoras or small loaches. You can also keep a pair of dwarf cichlids in a carefully structured layout with caves, wood and plants. The key is still balance: not just counting fish, but considering their behaviour, territory requirements and compatibility. Medium tanks allow for shoals that behave naturally instead of just surviving.

In this volume category, investing in a quality external canister filter from the start is usually wise. Such filters offer more room for biological media, better circulation and quieter operation. MB Store provides a wide selection of filters matched to tank sizes, as well as complete sets that pair the aquarium with an appropriate filter and heater. Proper filtration reduces the frequency of deep cleaning and supports stable conditions even when feeding is not perfectly controlled.

Lighting is another area where medium tanks truly shine. With a stronger LED system, you can grow a broader selection of plants, including more demanding stems and carpets. A planted aquarium not only looks impressive, but also functions as a natural filter by consuming nitrates and releasing oxygen. Combining good lighting, CO₂ supplementation and nutrient-rich substrate can transform your 120L tank into a densely planted aquascape. MB Store offers CO₂ sets, diffusers and fertilizers that are compatible with tanks in this range, so you can gradually increase the complexity of your setup.

Large Home Aquariums 180–300L: Stability, Scale and Impact

Once you cross the 180L threshold, you enter the world of large home aquariums that become a dominant decorative element in a room. The first immediate benefit is enhanced stability. In 200–300L of water, temperature swings are slower, and minor mistakes are less dramatic. This does not mean maintenance can be neglected; rather, it means you have more time to react and correct issues before they endanger fish and plants.

Large tanks offer entirely new possibilities for stocking. You can maintain impressive shoals of mid-sized tetras, barbs or rainbowfish, create biotope aquariums that resemble natural rivers or lakes, or set up communities with larger centerpiece fish such as angelfish, gouramis or peaceful cichlids. Thanks to additional swimming space and hiding places, aggression can be dispersed, and fish can establish natural hierarchies without constant conflict. Still, careful research and planning are essential, especially with territorial species.

Technical equipment for these volumes must be chosen with extra attention. Powerful external filters or even dual filtration systems are recommended to guarantee sufficient turnover and mechanical cleaning. MB Store offers filters specifically rated for 200–300L tanks, along with matching heaters and controllers. For heavily stocked or large planted aquariums, supplementary circulation pumps can help eliminate dead spots where debris tends to accumulate.

The weight and dimensions of large aquariums also require consideration. A full 300L tank with substrate, decor and cabinet can easily exceed several hundred kilograms. Proper support furniture is mandatory. At MB Store you can find dedicated stands and cabinets designed to bear the load and to provide hidden space for filters, cables and maintenance tools. Planning the location in your home is just as important as choosing fish species; once filled, such a tank is not easily moved.

Equipment Essentials for Every Aquarium Size

Regardless of whether you choose 25L or 300L, a few categories of equipment remain essential. The first is an appropriately sized filter providing both mechanical and biological filtration. Its job is to remove visible particles and host colonies of beneficial bacteria. Undersized filters lead to murky water and fluctuating parameters, while oversized filters can create excessive current in small tanks. MB Store’s product descriptions clearly state recommended volumes, helping you match the model to your aquarium.

The second element is a reliable heater, especially in homes where room temperature changes significantly between day and night or across seasons. Most tropical fish thrive between 24–26°C, so a stable temperature is one of the pillars of fish health. For very large aquariums, using two smaller heaters instead of a single large one can offer redundancy and more even heat distribution. Thermometers and, if necessary, controllers provide extra safety.

Lighting must be adapted to both the depth of the aquarium and the needs of your plants. Low-light species such as Anubias or Java fern cope well with basic LEDs in smaller tanks, while carpets and red stems in deeper or larger setups require more powerful lighting. MB Store stocks modern LED fixtures that are energy-efficient and often programmable, allowing dawn–dusk simulations and custom intensity schedules that enhance fish colours and reduce stress.

Other useful accessories include automatic feeders, air pumps, test kits, algae scrapers and siphons for water changes. Test kits are particularly important when setting up a new aquarium and during the first months of operation. Measuring ammonia, nitrite, nitrate and pH helps you understand how the biological cycle develops and whether your maintenance schedule is effective. All these products are available at MB Store, making it easy to assemble a complete toolkit for responsible aquarium care.

Planning Stocking and Aquascape by Volume

Proper stocking is not only a matter of numbers but also of structure. Before introducing any fish, it is worth deciding what role each species will play and how the aquascape will support their behaviour. In smaller aquariums, the layout should maximize open swimming space while still offering hiding places through plants and stones. Tall background plants or a large piece of wood can visually enlarge the tank and provide shelter without overfilling the limited floor area.

Medium tanks give more creative freedom. You can design distinct territories separated by rocks or driftwood, allowing shy or territorial fish to claim specific sections. Using plant groups in the midground and open sand or gravel in the foreground creates depth and natural visual flow. Shoaling fish look best when kept in sufficient numbers and in long tanks where they can move across the full length. This is where 80–150L aquariums start to show their true potential.

In large aquariums, aquascaping can become almost architectural. You can build slopes, terraces and complex root structures, creating vertical layers and sheltered zones beneath overhanging branches. Such structures are not mere decoration; they provide comfort and security to fish, especially in mixed communities. MB Store carries a wide selection of rocks, driftwood, substrates and background materials that can be combined to achieve virtually any style, from classic nature aquariums to biotopes imitating specific rivers.

Maintenance Routines for Different Aquarium Sizes

Many beginners believe that smaller aquariums are automatically easier to maintain. In reality, they often demand more frequent interventions. In a 25–40L nano setup, weekly water changes of 30–40% are usually essential, along with careful cleaning of the glass and filter media rinsed in tank water. Even modest overfeeding can quickly pollute the system, so restraint at feeding time is vital. Using high-quality foods and test kits from MB Store helps keep the small ecosystem under control.

Medium aquariums allow for slightly more relaxed routines, though regularity remains crucial. A common schedule for 80–150L tanks involves a 25–30% water change each week, pruning plants, vacuuming debris from the substrate and checking all devices. Filter maintenance may be needed every 4–8 weeks depending on stocking and feeding. It is best to clean only part of the filter media at a time to preserve beneficial bacteria and avoid disturbing the biological balance.

For large 200–300L aquariums, the volume itself works in your favour. Even so, dirt and algae will accumulate if neglected. Many aquarists choose to invest in tools that make maintenance easier: longer siphons, magnetic algae scrapers and dedicated buckets or hoses. MB Store offers such accessories, enabling efficient work without spilling water everywhere. With large tanks, planning the logistics of water changes becomes part of the hobby, but the reward is an impressive, stable display that demands less emergency intervention.

How MB Store Supports Your Aquarium Project

Successful aquaristics combines knowledge, planning and access to the right products. MB Store supports your project at every stage, from choosing the first 25L nano aquarium to setting up a 300L showpiece in your living room. The shop’s offer includes complete aquarium sets, individual glass tanks, stands, filters, heaters, lighting, substrates, test kits and decorations. Thanks to this, you can design a coherent system instead of assembling random components from different sources.

Another advantage of MB Store is the clarity of product descriptions and parameters. Information about recommended tank volumes, power consumption, dimensions and performance helps you make informed decisions rather than guesswork. Whether you are buying LED lighting for a planted tank or selecting an external filter for a 200L community aquarium, you can easily compare options and choose the most suitable model within your budget.

As your skills develop, MB Store also gives you access to more advanced solutions, such as CO₂ systems, automatic top-off units and specialized plant fertilizers. In combination with educational content, including guides like this one, these tools allow you to progress from simple beginner setups to complex aquascapes or biotope replicas. No matter the volume you choose, the right equipment and a thoughtful plan turn an empty tank into a thriving, living microcosm.

Summary: Matching Aquarium Size to Your Ambitions

Selecting the optimal aquarium size is not just a technical detail; it is the foundation of a sustainable and enjoyable hobby. Small 25–60L tanks fit limited spaces and budgets but demand precision and discipline. Medium 80–150L aquariums offer the most balanced combination of stability, creative freedom and manageable maintenance. Large 180–300L setups require more planning and investment, yet reward you with impressive displays and greater margin for error.

Before purchasing, consider your available space, time for maintenance, electricity costs and long-term goals. Are you dreaming of a lush planted scape with shrimp, a colourful community of schooling fish, or a biotope with larger centerpiece species? Once you answer these questions, you can choose the volume that best supports your vision. MB Store stands ready to provide the aquariums, equipment and accessories needed to bring that vision to life, from the smallest nano to the most ambitious 300L underwater landscape.

FAQ

What aquarium size is best for a complete beginner?
For most beginners, a tank between 80 and 120 litres is ideal. This volume offers relatively stable water parameters and enough space for a small, peaceful community of fish and plants, yet it is still easy to place in an average room. Very small tanks react too quickly to mistakes, while very large ones require more planning, equipment and higher initial costs.

Can I keep fish in a 25L aquarium, or is it only for shrimp?
A 25L aquarium can host fish, but they must be carefully selected micro species or a single betta. Stocking should be very modest to avoid overloading the limited biological capacity. Many aquarists prefer shrimp and snails in this volume, as their bioload is lower. Whatever you choose, proper filtration, heating and regular water changes are essential for long-term success.

How often should I change water in a 200–300L aquarium?
For a well-filtered, reasonably stocked 200–300L aquarium, a weekly water change of about 25–30% is usually sufficient. This schedule keeps nitrate levels manageable and replenishes essential minerals. In heavily stocked or high-tech planted tanks, you may need slightly larger or more frequent changes. Regular testing will help you fine-tune the routine and avoid both neglect and unnecessary over-maintenance.

Do I really need an external filter for a medium-sized tank?
While internal filters can work in medium aquariums, an external canister filter usually provides better mechanical and biological filtration, more media volume and quieter operation. For tanks in the 80–150L range, a quality external filter offers greater stability, clearer water and easier maintenance. It also frees space inside the tank, improving aesthetics and giving fish more room to swim.

How do I know if my chosen light is strong enough for plants?
The right light intensity depends on tank depth and plant types. Low-light plants cope with modest LEDs, especially in shallow tanks. For dense carpets or red stems, you need stronger lighting and often CO₂. Check manufacturer recommendations for the fixture and compare with plant requirements. If growth is slow, colours pale and algae moderate, you may need more light, while excessive algae suggests too much intensity or imbalanced nutrients.