The 10 Easiest Aquarium Fish for Beginners
, by Michael van Wassem, 7 min reading time
The 10 easiest aquarium fish for beginners: hardy species, group size and tank size at a glance, with a comparison table and common mistakes.
Your tank is set up, the water is ready, and now comes the most enjoyable question: which fish should move in first? Not every fish you see swimming at the shop is a good choice as a first resident. Some species need such stable water parameters that even small swings make them ill, while others seem almost made for a brand-new aquarium.
Direct answer: The easiest fish for beginners are hardy, sociable species that tolerate small swings in temperature and water parameters well, such as guppies, platies, swordtails, zebra danios and corydoras catfish. As a beginner, avoid sensitive species such as neon tetras in a freshly cycled tank, cichlids with specific requirements, and only keep goldfish in a tank of at least 75 to 100 litres.
What makes a fish suitable for beginners?
A tank that has only been running for a few weeks doesn't yet have perfectly stable water parameters, even if it was cycled by the book. Fish that cope well with that tend to share these traits:
- Tolerance for water parameters - the fish survives a small spike in ammonia or nitrite without falling ill straight away.
- Sociable, but not fragile - the fish lives well alongside other peaceful species, without becoming stressed easily itself.
- Predictable adult size - you know in advance how big the fish will get and whether it will fit your tank.
- Widely available and healthily bred - many captive-bred strains are hardier than wild-caught fish and easier to find at a reputable shop.
Haven't set up your tank yet? Start with our complete checklist for setting up an aquarium, so the water is ready before the first fish arrive.
The 10 easiest aquarium fish for beginners
These ten species combine sturdy health with a friendly temperament, and are available at almost any aquarium specialist.
1. Guppy (Poecilia reticulata)
For many aquarists, the guppy is their first fish, and not without reason: colourful, active and very tolerant of water parameters. Guppies are livebearers and breed easily, so expect a growing population. From 40 litres and a group of at least five is a good start. A flake food specifically formulated for guppies suits their small mouths well.
2. Platy (Xiphophorus maculatus)
Platies resemble guppies but are a little stockier and even more forgiving of beginner mistakes. Calm, available in many colours, they do well in a community tank from 40 litres, in a group of at least five.
3. Swordtail (Xiphophorus hellerii)
Swordtails are active swimmers that appreciate a bit more length, from around 80 to 100 centimetres of tank width. Keep a ratio of at least two females per male, otherwise a male quickly becomes too pushy towards the rest of the group.
4. Molly (Poecilia sphenops)
Mollies are hardy and sociable, but do best in slightly harder water than the average tropical fish. They thrive in a group of at least six and are, like guppies and platies, livebearers.
5. Zebra danio (Danio rerio)
Few species are as unbothered by temperature swings as the zebra danio. This small, striped shoaling fish is constantly on the move and does best in a group of at least six, in a tank with enough room to swim.
6. White Cloud Mountain minnow (Tanichthys albonubes)
This small, hardy shoaling fish originally comes from cooler mountain streams and can therefore be kept without a heater, as long as room temperature doesn't drop too far. Ideal for a calm, understated community tank from 40 litres.
7. Corydoras catfish
For the bottom of the tank, corydoras are an excellent choice: a calm, shoaling catfish that tidies up leftover food and rarely causes problems. Keep them in groups of at least six and provide a soft, rounded substrate, since their sensitive barbels are quickly damaged by sharp gravel.
8. Siamese fighting fish (Betta splendens)
The betta is a striking loner: beautifully coloured, but not suited to living with others of its own kind because of its territorial behaviour. A tank from 20 litres with a heater and gentle flow is enough for one fish, possibly alongside calm bottom-dwellers.
9. Dwarf rainbowfish (Melanotaenia praecox)
This vivid blue shoaling fish is a little more active and needs a bit more swimming space than the previous species, but is still well suited to beginners. A group of at least six in a tank from 80 litres shows its colours off best.
10. Goldfish (Carassius auratus)
Goldfish are often underestimated: they're hardy coldwater fish, but they grow substantial and produce a lot of waste. Allow for at least 75 to 100 litres for the first goldfish, plus extra volume for every fish you add. Never keep them in a bowl - that's not suitable for any fish.
Comparison table: at a glance
| Fish | Min. tank size | Water temperature | Group size |
|---|---|---|---|
| Guppy | 40 litres | 22-28 °C | 5+ |
| Platy | 40 litres | 20-26 °C | 5+ |
| Swordtail | 80-100 litres | 20-26 °C | 5+ |
| Molly | 60 litres | 24-28 °C | 6+ |
| Zebra danio | 60 litres | 18-25 °C | 6+ |
| White Cloud Mountain minnow | 40 litres | 18-22 °C | 6+ |
| Corydoras | 60 litres | 22-26 °C | 6+ |
| Siamese fighting fish | 20 litres | 24-28 °C | solo |
| Dwarf rainbowfish | 80 litres | 23-27 °C | 6+ |
| Goldfish | 75-100 litres | 10-22 °C | 1+, plus volume per fish |
Which fish are better avoided for now?
Some popular fish are precisely not a good first choice. Neon tetras and other small tetras look simple, but are fairly sensitive to fluctuating water parameters and only do well in a tank that's been running for longer. Discus and most cichlids have such specific requirements around water parameters and behaviour that they're better suited to experienced aquarists. And however cute it looks, a single goldfish in a bowl without a filter is not a viable environment for any fish.
Common mistakes when choosing your first fish
- Buying fish before the tank has cycled - without the right bacterial culture, ammonia and nitrite levels rise quickly.
- Combining species without research - not every peaceful fish suits every other community tank; always check temperament and water requirements.
- Underestimating adult size - a swordtail or goldfish grows considerably bigger than the young fish you see in the shop.
- Too few individuals of a shoaling fish - a group of two or three zebra danios or corydoras stays stressed; aim for at least five to six.
- Adding a whole group at once - introduce fish in stages, so the bacterial culture in the filter can keep up.
Checklist: before you buy fish
- Check that ammonia and nitrite in your tank read 0.
- Choose species that suit your tank size and each other.
- Stick to the recommended group size for each shoaling fish.
- Use a water conditioner to make tank water safe straight away.
- Add fish in small groups, a few weeks apart.
- Choose the right food per species, matched to mouth shape and diet.
Frequently asked questions
Can I keep several species from this list together?
In most cases, yes. Guppies, platies, swordtails, mollies, zebra danios, White Cloud Mountain minnows, corydoras and dwarf rainbowfish combine well. The Siamese fighting fish is best kept alone or with calm bottom-dwellers, and goldfish aren't combined with tropical species because of the temperature difference.
How many fish can my tank hold?
That depends on the volume, the filter and the adult size of the fish. When in doubt, stay cautious and only expand the stock once water parameters remain stable.
Do I always need a heater?
For most species in this list, yes. Only the White Cloud Mountain minnow and the goldfish can do without, provided room temperature doesn't drop too far.
Why aren't neon tetras recommended for beginners?
Neon tetras are sensitive to fluctuating water parameters and do better in a tank that's been stable for longer, not in the first weeks after cycling.
Summary and conclusion
Choosing the right fish doesn't start with the prettiest colour, but with the question of whether a species suits your tank and your experience. Guppies, platies, swordtails, mollies, zebra danios, White Cloud Mountain minnows and corydoras together form a solid basis for a community tank, while the Siamese fighting fish and the goldfish have their own needs that are worth knowing in advance. Starting this way builds a tank that both the fish and the owner will enjoy for years.
Disclaimer: this article is intended as general information. If in doubt about specific fish species or water parameters, consult a specialist aquatics shop.
Tags
Also worth reading!
-
, by Michael van Wassem Choosing bird toys: which toy suits your bird?
Choosing bird toys: which toy suits your bird? -
, by Michael van Wassem Chinchillas as pets: what you need to know before you start
Chinchillas as pets: what you need to know before you start -
, by Michael van Wassem Your Cat Through Autumn: Shedding, Warmth and Safety in the Dark
Your Cat Through Autumn: Shedding, Warmth and Safety in the Dark
