7 Best Aquarium Fish For Beginners

If you are a first-time fish tank owner, it can be hard to know which breeds to pick to fill it. They all require different levels of maintenance and tank sizes and can need a life alone or in a school.

The main thing to get out of the way is that freshwater is much easier to deal with compared to salt water, making it the best option for beginners. Then there is the choice of tropical or cold water, but the former just needs a suitable heater and thermometer added to the tank so there isn’t too much difference.

There is more choice for tropical, but we have included both below. These fish are in no particular order and all offer a host of different benefits and visual impacts.

What to consider if you’re a beginner fish owner

It is important to remember that if you mix the breeds of fish in your tank, you must try to find close matches in terms of the food they eat, how they feed, their behaviours and adapt the space they have.

Diet

Look for fish which are easy to find food for, so will eat pellets and flakes of either veg or meat

Size

Larger tanks are easier to look after, but you probably don’t want something too extreme so find a fish which will suit your chosen tank. Buy the largest possible, though, as this will give you the greatest range of possibilities and allow for growth or changes in how many you can keep

Friendliness

Some fish work better in communities than others. If you don’t want infighting, find a friendly breed

Hardy

They don’t need too much precision when it comes to water temperatures and a few degrees difference will help you out. Same with pH levels

The best fish for beginners

Tetra

• Water Temperature: 24-25.5°C
• School: Yes
• Potential Size: Depends on the species
• Tank Requirements: 50L+
• Food: Carnivores
• Life Span: 5-10 years

A small schooling fish, tetras are usually very docile and undemanding. They should live in groups of six or more, as they enjoy safety in numbers, which can make for a really lovely, colourful display.

They will usually eat any form of food, which makes the care side of things easy. Tanks should be filled with plants, decor and rocks in which they can hide as they are quite shy. The water can be easy to maintain as they like neutral pH waters from 7.0 to 7.8.

Originally coming from warm, murky jungle waters, they don’t like much light which should also help keep their tank low maintenance. Opt for an aquarium which is as spacious as possible.

There are over 700 subcategories, such as neon tetras, cardinal tetras, black neon tetras, and Congo tetras and they all vary in terms of potential size and behaviours so it is important to research.

Swordtails

• Water Temperature: 18-28°C
• School: Yes
• Potential Size: 6”
• Tank Requirements: 70L+
• Food: Omnivores
• Life Span: 3-5 years

One of the best fish in terms of not needing to get everything to exact precision. They can live between 18 and 28 degrees Celcius and in pH levels between 7.0 and 8.4, so there is room for slight changes.

Peaceful and sociable, they do best in small schools or with other similar fish such as platies, angelfish and tetras which are all similarly calm. But do be aware that males are usually always aggressive towards other males in their species, so having a ratio of males to females is important.

They are quite average-sized, so don’t need too much space in terms of this, yet are quite active so need plenty of room to swim around in. You should opt for around 70L per fish. Males are usually slightly smaller than females, at just under six inches.

Betta

• Water Temperature: 25.5-26.5°C
• School: No
• Potential Size: 3”
• Tank Requirements: 15L+
• Food: Carnivores
• Life Span: 3 years

Once more commonly known as Siamese Fighting Fish. They’re a warm water fish, and as the former name suggests, they have had a bad rap over the years for being aggressive.

This was often a bit harsh, though – the behaviour was usually from males and a primarily sexual. Still, keeping them on their own or with peaceful, compatible community fish is the most common way. You should limit this to one male and one female.

They are some of the prettiest fish with their vivid scales and long, flowing tails and fins. They’re quite small, and a general rule is that they need one gallon of water per inch so something just around 15L should suffice, and they will eat most meat-based pellets and fish foods.

Our friends over at The Witty Fish have put together this great guide to Betta fish, which is worth a read if you’re considering keeping Siamese Fighting fish as pets.

Guppies

• Water Temperature: 22-28°C
• School: Yes
• Potential Size: 2.5”
• Tank Requirements: 20L+
• Food: Omnivores
• Life Span: 2 years

A school fish, known for their vivid fan-like tails. They can eat a variety of foods, and can even go a week without food (although this obviously isn’t recommended), so are very low-demand.

They are quite small, with the males having larger tails than the females. For this reason, it is often best to not mix them with other breeds of fish, as they could be eaten. But when living with each other, they’re peaceful and quite active.

A vital thing to know is that they breed an awful lot, and can have up to 60 babies per litter. These are all born alive, and it would drastically change the demands and capacity of your tank should this happen. You should keep one guppy per 5-10L of water.

In the wild, females are typically grey and males have colourful stripes, spots or splashes, but this domestic breeding has caused over 300 varieties, and a whole host of colour combinations and patterns.

Catfish

• Water Temperature: 22-28°C
• School: Yes
• Potential Size: 2-24”
• Tank Requirements: 45L+
• Food: Omnivores
• Life Span: 5-15 years

These are some of the most interesting beginner fish for home aquariums. There’s a wide range of species available, and there’s often some best options for whether you have a tropical, cold water or even a marine setup.

Available in various sizes, you can also purchase one which can fit right into your existing tank so you don’t need to change anything. They are benthic, meaning they dwell on the bottom of the tank on the substrate, eating the algae and waste left behind by the other fish like a free mini vacuum cleaner. Corydoras and pleco are perhaps the most common species.

Slow-moving and calm, the ones you’d have in your tank are not known for attacking other fish or eating smaller breeds. But they should not be housed with aggressive fish as they can become prone to being victims of bullying. Larger species may be vicious, though.

If you have any other fish and feed them floating flakes, be aware your catfish could go hungry so always give them some sinking pellets and keep an eye on them. The average lifespan is eight years but depends on species.

Common Goldfish

• Water Temperature: 20-22°C
• School: Ideally
• Potential Size: 7-14”
• Tank Requirements: 50L+
• Food: Omnivore
• Life Span: 10 years

You may often see these recommended by professionals as what not to keep. They can grow surprisingly large, and many need to be transferred outside into ponds once they outgrow an internal tank.

Common goldfish (Carassius auratus) usually grow to around 7 or 8” if not crowded, with some even reaching 14” or more over the years. Around 25L should be given per average-sized goldfish, but you can’t really give them too much space so the bigger the better.

They’re good for beginners because they are resilient and easy to care for. Coldwater, they need regular water changes but will generally eat any standard fish food. They are generally quite comfortable and sociable, but you should ensure their tank is at least 50% hiding places so they have the safety to retreat to.

They can be kept with fish which require the same temperatures and show similar behaviour, which often limits you to other goldfish species but there are dozens to choose from. They’re best kept in at least pairs, as singular fish can become lonely.

Be prepared if yours does grow large. If you have a suitable pond, they may need to be transferred. The average pet goldfish will live to be 10 years old, but in the wild, they can reach over 40.

Dwarf Gourami

• Water Temperature: 22-28°C
• School: No
• Potential Size:
• Tank Requirements: 20L
• Food: Omnivore
• Life Span: 4 years

A peaceful and shy fish, the gourami has a unique slow, mesmerising swimming style and vivid colouration depending on the sex.

Best kept in a male/female pairing, they are good for anyone who doesn’t want an entire school of fish to keep an eye on. The good news is that they’re peaceful, so as long as there aren’t two males who could battle it out, you should have a calm tank.

Mixing with other peaceful species is possible, but they shouldn’t be too colourful as the males can become jealous. They shouldn’t be kept with large, aggressive fish. A quiet location is best, with plenty of plants for hiding opportunities.

They are labyrinth fish, which means that they breathe straight from the air so need access to the water surface.

Related guide: how to clean a fish tank

Related: Live Plants for Fish Tanks