Choosing the Best Fish for Your First Aquarium

Starting a first aquarium is an exciting step into a calm, nature‑inspired hobby. The choice of fish, however, will decide whether your new tank becomes a stable, colourful ecosystem or a source of constant problems. Before you bring home the first attractive species you see in a shop, it is worth understanding which fish really suit beginner aquarists, what they need to thrive and how to match them with the right aquarium and equipment. In this guide we will walk through the basics of smart fish selection, with practical examples and clear recommendations. Throughout the text you will also find references to essential gear available at MB Store, where you can choose reliable aquariums and accessories that make your first setup much easier to manage.

Key principles when choosing fish for a first aquarium

The first rule of choosing fish is simple: select species for your water, not water for your species. Many beginners fall in love with a particular fish and then try to bend all conditions around it. This quickly leads to frustration. It is far safer to choose hardy species that tolerate a wider range of parameters and adapt well to typical tap water when properly treated with a good conditioner and filter system, such as those offered by MB Store.

Another core principle is to respect the adult size of the fish. Tiny juveniles in the shop often grow into large, powerful swimmers that demand far more space and filtration than a starter tank can give. A common mistake is placing energetic shoaling fish in a tank that is too small, which leads to stress, aggressive behaviour and disease. Reading about the adult size, temperament and social needs of any species before buying is therefore essential.

A stable aquarium depends heavily on biological balance. That means your stocking level must match both your tank volume and the capacity of your filter. Overcrowding is the fastest way to algae blooms, cloudy water and frequent illness. For beginners, it is wise to stock the tank slowly, starting with just a few hardy individuals, testing water parameters regularly and adding more fish only after the system shows stability for several weeks. MB Store provides not only aquariums of different sizes, but also test kits and filters that help keep that balance under control.

Compatibility is another critical factor. Some species are peaceful, others territorial or even predatory. Combining them randomly can end with nipped fins, constant chasing or fish simply disappearing. Books and online resources are useful, but nothing replaces a clear stocking plan written down before you buy anything. Group fish by water parameters, temperament, activity level and size. If you plan a community tank, look for species that share similar needs and are known to coexist peacefully.

Understanding your first aquarium setup

Fish choice cannot be separated from the aquarium itself. A 30‑litre tank offers very different possibilities than a 120‑litre one. In general, beginners benefit greatly from starting with the largest aquarium they can realistically fit and maintain. Larger water volumes dilute waste more effectively and buffer against rapid changes in temperature or chemistry, making them far more forgiving. MB Store offers a wide range of glass tanks, from compact desktop models to spacious family‑room aquariums, so you can match your ambitions with available space.

Filtration is the beating heart of a healthy aquarium. A good filter provides mechanical cleaning, trapping particles, and biological filtration, where beneficial bacteria process toxic ammonia and nitrite into less harmful nitrate. When choosing fish, always keep in mind the bioload they will place on your system. Heavily feeding or messy species need stronger filtration, while lightly stocked nano tanks can use more modest filters. At MB Store you can find internal filters, hang‑on‑back models and canister filters suited to both small and large aquariums.

Substrate, decorations and plants also influence fish selection. Bottom dwellers such as Corydoras or loaches appreciate soft sand where they can safely sift without damaging delicate barbels. Rock structures and caves are ideal for shy or territorial species that require clear boundaries. Live plants provide shelter, natural filtration and oxygenation, though they also require suitable lighting and sometimes fertilisers. When planning a first tank, think of the overall layout as a landscape built for the comfort of your future fish, and choose hardscape and plants available at MB Store accordingly.

Water parameters deserve careful consideration. Temperature, hardness and pH shape which species will truly thrive. Many common community fish adapt well to moderately hard, slightly alkaline tap water kept at around 24–26°C. Those characteristics make them excellent candidates for beginners. Fish that demand very soft or very acidic water, or extremely warm temperatures, are better left for later projects once you have more experience and equipment such as reverse osmosis systems or specialised heaters.

Ideal beginner fish species for community tanks

Community tanks are the classic first aquarium choice: a mix of small, peaceful species that coexist in a single display. Several hardy fish stand out as outstanding options for newcomers. Livebearers like guppies, platies and mollies are extremely popular due to their bright colours and active behaviour. They tolerate a range of water conditions, breed readily and are easy to feed with quality flake foods. Keep in mind, however, that their rapid reproduction can quickly fill a small tank, so plan stocking numbers accordingly and consider separating sexes if needed.

Schooling fish bring movement and harmony to the middle and upper levels of the aquarium. Small tetras, such as neon tetras, black neon tetras or ember tetras, are attractive and relatively undemanding when kept in stable, well‑filtered water. They must be kept in groups of at least six to feel secure and show natural behaviour. Rummy nose tetras and harlequin rasboras are slightly more sensitive but still accessible to attentive beginners who perform regular water changes and testing.

For the bottom zone, peaceful catfish species such as Corydoras are ideal. They patrol the substrate in cheerful groups, searching for leftover food and helping to keep the tank tidy. It is a myth, however, that they survive solely on scraps; they still need dedicated sinking pellets and occasional frozen foods. Corydoras enjoy being in groups of six or more and adapt best to softer, fine substrates rather than sharp gravel. Pair them with mid‑water schooling fish and you will quickly create a dynamic yet tranquil community.

Another friendly bottom dweller is the bristlenose pleco, which remains relatively small compared with common plecos and is famous for grazing on algae. While helpful, it should not be considered a replacement for proper maintenance. Bristlenose plecos need pieces of driftwood to rasp on, hiding places and varied food including algae wafers and blanched vegetables. In a well‑planned tank with adequate filtration from MB Store equipment, they can be long‑lived, characterful additions to a first aquarium.

Robust species for nano and desktop aquariums

Not everyone can start with a large tank, and compact aquariums remain very popular. Small volumes require more discipline because water parameters can fluctuate faster, so fish choice becomes even more important. Some of the best candidates are small, hardy species such as endlers, which are close relatives of guppies but usually stay slightly smaller. In a densely planted nano tank they display vibrant colours and fascinating social behaviour. Just like guppies, they breed actively; a balanced population often includes more males than females to reduce constant mating pressure.

Another excellent option for nano setups is the betta, also known as the Siamese fighting fish. Bettas are solitary by nature and should not be kept with other male bettas. In a properly heated and filtered tank of adequate size, they reward their keeper with flowing fins and an impressive range of colours. Their labyrinth organ allows them to breathe atmospheric air, but this should not serve as an excuse to keep them in unheated bowls or vases. A small rectangular tank with a gentle filter and stable temperature, such as those sold by MB Store, creates conditions in which a betta can display its full personality.

Small rasboras like chili rasboras or microdevario species can also work in nano aquariums, provided you focus on stable parameters and frequent partial water changes. Because of their tiny size, they appreciate dense planting and subdued lighting. They are best kept in calm surroundings without large, boisterous tankmates. Shrimp‑focused nano setups can be supplemented with tiny, peaceful fish that do not hunt adults, though shrimp juveniles will always be somewhat vulnerable, so consider your priorities when mixing these animals.

Fish species beginners should avoid at first

Some fish, despite being common in pet shops, are poor choices for a first aquarium. Large, fast‑growing species like common plecos, many cichlids or certain barbs quickly outgrow small tanks and become aggressive or stressed. Goldfish, often marketed as suitable for bowls, actually produce a great deal of waste and need spacious, well‑filtered cold‑water setups, making them challenging for those just starting with tropical community tanks.

Delicate or highly specialised fish also present difficulties. Certain wild‑caught tetras, rasboras and dwarf cichlids demand very soft, acidic water and pristine conditions that are hard to maintain without advanced equipment. Similarly, many marine species, such as mandarinfish or anemonefish kept with real anemones, require mature saltwater systems with stable parameters and strong lighting, far beyond the needs of a simple beginner setup. It is wise to build experience with hardy freshwater species first before moving into such niches.

Another group to treat with caution includes highly territorial or predatory fish. Some cichlids, pufferfish and large catfish can exhibit behaviours that surprise newcomers, from fin‑nipping to hunting smaller tankmates. Without a deep understanding of their needs and appropriate tank space, these species often end up suffering or being returned. To avoid such problems, concentrate initially on peaceful species known for compatibility and resilience, building skills in aquarium maintenance, observation and water chemistry before experimenting with more demanding animals.

How many fish can you keep? Stocking and bioload

Determining how many fish a tank can support is as important as choosing species. Traditional rules such as one centimetre of fish per litre oversimplify the issue and can be misleading. Bioload depends not just on length but also on body mass, activity level, diet and the efficiency of your filtration and maintenance routine. A group of slender, calm tetras exerts less pressure on the system than an equal total length of bulky, constantly moving cichlids.

For beginners, a more reliable approach is to start low and increase cautiously. After cycling the aquarium and confirming that ammonia and nitrite remain at zero for a few weeks, add only a small group of fish and monitor the response. Test water regularly, observe fish behaviour and watch for signs of stress like rapid breathing, hiding or clamped fins. If parameters stay stable and fish remain healthy, you can add further groups following your stocking plan, always allowing the filter bacteria time to adapt.

Regular maintenance is central to keeping bioload under control. Partial water changes, careful feeding and filter cleaning according to manufacturer instructions all contribute to a stable environment. Overfeeding is a particularly common mistake; uneaten food decays, producing ammonia and fuelling algae growth. Offering small portions that fish can consume within a few minutes, once or twice a day, is usually sufficient for healthy, well‑conditioned fish. Using reliable filters, heaters and cleaning tools from MB Store greatly simplifies this routine and helps maintain consistent conditions.

Matching fish with plants and decor

A well‑designed aquascape does more than please the eye; it directly affects fish health. Species that naturally inhabit densely vegetated streams feel safer among live plants, which provide visual barriers and reduce stress. Peaceful community fish such as tetras, rasboras and many livebearers thrive among stems, floating plants and mosses. Plants also absorb nitrate and other nutrients, complementing your filtration system and boosting water quality.

Some fish interact with their environment in specialised ways. Certain catfish species require driftwood; others prefer rock piles or leaf litter. Understanding these preferences allows you to create microhabitats within the aquarium so different species can occupy distinct zones without constant confrontation. Sand banks, stone caves and shady areas under broad leaves all contribute to a more natural, functional layout. With the wide selection of substrates, stones, roots and plants available at MB Store, it is easy to assemble a personalised aquascape tailored to your chosen fish.

Lighting intensity and colour also influence both plant growth and fish comfort. Bright, cool‑white lights may bring out vivid colours but can make shy species retreat. A moderate, adjustable LED system is ideal for most beginners, allowing gradual adaptation. Darker substrates and backgrounds help fish feel secure and enhance their colours, while also reducing reflections that might confuse or disturb them. When planning the visual style of your tank, always ask how each choice will affect the daily lives of the animals you intend to keep.

Essential equipment from MB Store for a successful start

Even the best fish choice cannot compensate for inadequate equipment. A reliable heater, filter and lighting system form the technological foundation of every aquarium. MB Store offers comprehensive sets that include carefully matched components, minimising the risk of incompatible or underpowered gear. For those who prefer custom setups, you can select individual tanks, filters, heaters, lights and accessories to construct a solution tailored to your space and budget.

Beyond the main devices, certain smaller tools make daily care much easier. Water conditioners neutralise chlorine and heavy metals in tap water, protecting sensitive gill tissues and beneficial bacteria. Test kits for ammonia, nitrite, nitrate and pH provide insight into the invisible chemistry of your tank, allowing early intervention before problems escalate. Nets, algae scrapers, siphons and food dispensers are simple but essential items that streamline maintenance and reduce stress for both keeper and fish.

For those who value aesthetics and long‑term stability, MB Store also supplies substrates, plant fertilisers, root tabs and CO₂ systems that support vigorous plant growth. Healthy plants not only beautify the aquarium but also create a more natural environment for fish, offering hiding places and breeding sites. With the right combination of hardy fish, robust plants and dependable equipment, your first aquarium can become a thriving, low‑stress ecosystem rather than a constant struggle.

Observation, patience and long‑term planning

Choosing the best fish for your first aquarium is ultimately about patience and realistic planning. Instead of rushing to fill the tank, focus on understanding the needs of each species and how they interact. Spend time observing fish in shops and established display tanks. Look for clear eyes, intact fins, steady swimming and regular breathing. Avoid specimens that float listlessly, hide constantly or display spots, frayed fins or unusual growths.

Once your own tank is running, observation becomes your most powerful tool. Fish often show subtle behavioural changes before visible illness appears. By watching feeding responses, social interactions and territorial displays, you can detect early signs of stress and correct the cause, whether it is water quality, overcrowding or incompatible tankmates. Keeping a simple notebook or digital log of test results, maintenance tasks and new additions helps maintain perspective over weeks and months.

Long‑term success in aquaristics comes from making thoughtful decisions at every stage. Begin with hardy, peaceful fish, supported by solid equipment from MB Store and a well‑planned aquascape. As your confidence and understanding grow, you can gradually explore more demanding species, larger tanks or specialised biotopes. The most satisfying aquariums are those that reflect both the natural needs of their inhabitants and the personal style of their keeper, forming a living landscape that evolves over time.

FAQ

What size aquarium is best for a beginner?
For most beginners, an aquarium between 60 and 100 litres offers the best balance between stability and practicality. The larger water volume dilutes waste and slows parameter swings, making mistakes less dramatic. Such tanks also allow small groups of different species, so fish can behave naturally. MB Store provides complete sets in this range, including filters and heaters designed for easy first setups.

How long should I wait before adding fish?
Before adding fish, you must cycle the aquarium so beneficial bacteria can process toxic ammonia and nitrite. This usually takes three to six weeks, depending on temperature, filtration and any bacterial starters you use. During this time you should test water regularly and add a source of ammonia, such as fish food. Only when ammonia and nitrite stay at zero for several days is the tank ready for its first hardy inhabitants.

Can I mix any beginner fish species together?
Not all beginner‑friendly fish are compatible. Some prefer harder, alkaline water, while others require softer conditions. Temperament matters as well: peaceful schooling fish may suffer if housed with fin‑nippers or territorial species. Always check adult size, water parameters and behaviour before combining fish. Aim for groups of species with similar needs and avoid overcrowding. Staff at MB Store can help you create safe stocking plans.

Do I really need live plants in my first aquarium?
Live plants are not absolutely required, but they bring many benefits. They use nitrate and other nutrients, improving water quality, and provide shelter that reduces stress. Many fish display better colours and more natural behaviours in planted tanks. For a first aquarium, choose hardy species like Anubias, Java fern or Vallisneria, which tolerate a wide range of conditions and simple lighting. MB Store offers these plants and matching substrates.

How often should I change water in a beginner tank?
In most beginner aquariums, changing 20–30 percent of the water every week is a good routine. This removes accumulated nitrate and other substances that filters cannot fully eliminate. Always treat new tap water with conditioner and match temperature to avoid shocking your fish. Consistent water changes, combined with moderate feeding and appropriate stocking, keep the environment stable. Simple siphons and conditioners from MB Store make the process quick and safe.