Which Fish Is Best For a First Aquarium? (3 & 4 are Hard to Beat)

by Kevin

Celestial Pearl Danio in a planted aquarium.

If you are planning on setting up your first aquarium, or if you have one set up but haven’t added fish yet, then you may be wondering, “which tropical fish are best for a first-time aquarium?”

This article will answer that question, but keep mind that these picks are based on my personal experiences keeping tropical fish, and I haven’t kept every tropical fish available (yet) so the list will be updated periodically.

The criteria I’m basing my list on is 1) hardiness, 2) interest/beauty, and 3) availability.

Basically, the fish below can tolerate a wide range of water conditions, are full of personality and/or look stunning, and are widely available so that you can find them in a pet shop or online.

1. Zebra Danios (Danio rerio)

Zebra danio for a first aquarium.

At the top of the list is the Zebra Danio.

Zebra Danios are small, but resilient fish that tolerate a wide range of water conditions.

Their streamlined bodies give them a minnow-like appearance, making these fish ideal for nature style aquariums.

Zebra danios are nervous fish, so keeping them in groups of 5-6 fish is ideal.

Because they are relatively small fish, 1 inch (2.5 cm), they make great inhabitants for 5 gallon and 10 gallon aquariums.

2. Celestial Pearl Danios (Danio margaritatus)

Celestial pearl danio for first aquarium.

One of the most striking danios in the aquarium hobby is the Celestial Pearl Danio.

These fish are similar in shape to zebra danios but have striking blueish bodies, dotted with white spots, and vibrant red fins.

Celestial Pearl Danios used to be known as Galaxy Rasboras, but scientists figured out that these fish are more closely related to Danios than Rasboras, so these fish were given the new common name of “Celestial Pearl Danio.”

Celestial Pearl Danios prefer to be in groups (4-6 fish), and look incredible in aquascapes and heavily planted tanks.

3. Guppies (Poecilia reticulata)

Male guppies for first aquarium.

Guppies are a common recommendation for beginners, so you might be wondering if they are actually worth keeping.

The answer is yes.

Guppies are fun happy-go-lucky fish that are available in a unimaginable variety of colors and patterns.

I recommend getting group of males if you don’t want to have a tank full of baby guppies, but breeding them can also be an educational and fun experience for kids.

If you want to learn about keeping guppies, check out my article on male vs female guppies.

Guppies do great in tanks from 5-gallons to 20+ gallons, with a 10 gallon tank being the best size for a beginner (at least in my experience).

4. Betta Fish (Betta splendens)

Betta fish for first aquarium.

Betta fish are both colorful and full of personality.

A betta fish is an ideal fish for a first aquarium because they are hardy, display interesting behavior (like flaring), and do great in a 5-10 gallon aquarium.

One downside to betta fish is that they can’t be kept with other bettas, nippy fish, or fish that trigger their aggression.

So, if you do choose a betta fish for your first aquarium, choose your betta’s tank mates carefully, or keep your betta by himself/herself.

5. Mollies (Poecilia spp.)

Lyretail Molly (Poecilia latipinna)
Lyretail Molly (Poecilia latipinna)

Like Guppies, Mollies are livebearers with lots of personality.

They are available in a variety of shapes and colors and make excellent tank mates for other fish.

One of my favorites types of Mollies are Balloon Mollies; their round body shapes are comical and charming.

You can’t go wrong with getting mollies for a first aquarium.

6. Cherry Barbs (Puntius titteya)

Cherry barb for first aquarium.

Cherry barbs are a great option for those who want to add a reddish colored fish to a small aquarium.

These barbs are peaceful fish and enjoy being in groups of four to six, which is the ideal amount for a 10 or 20 gallon tank.

Cherry barbs do well in a wide range of water conditions, making them a suitable choice for first-time aquarists.

I find that they do especially well in heavily planted tanks, which provide hiding places for these somewhat nervous fish.

7. Endler’s Livebearer (Poecilia wingei)

Endler's livebearer for frist time aquarium.

Endler’s livebearers are small, colorful, and active, making them one of the best beginner-friendly fish for small tanks (3-5 gallons).

Male Endler’s are quite small, typically reaching a maximum length of 1 inch, while females grow up to 1.8 inches.

Like guppies, they are livebearers, giving birth to live young instead of laying eggs.

To prevent your tank from being overrun with babies, I suggest keeping a small group of male Endler’s (3-6) for a first aquarium.

8. Bolivian Ram (Microgeophagus altispinosus)

Bolivian ram in a planted tank.

Bolivian Rams are a peaceful cichlid with big eyes and big personalities.

They are very peaceful (at least for a cichlid) and I highly recommend them to first time cichlid keepers.

Skip getting an Oscar, they are also beautiful but they become enormous.

Bolivian rams grow to about 3 inches in length, making them much more manageable than other types of cichlids.

A pair of Bolivian rams will do well in a 15 gallon tank, but a 20 gallon long is my preferred size for these beautiful cichlids.

9. Tiger Barbs (Puntigrus tetrazona)

Tiger barb for a first aquarium.

Tiger Barbs have orangish bodies with distinct vertical black stripes.

They can be nippy toward other fish, especially long-finned and slow moving fish like bettas, but do great when kept in a Tiger Barb only aquarium.

They are considered semi-aggressive so make sure to select their tank mates carefully.

Tiger barbs do best in groups of 4-6, so a 20 gallon aquarium is ideal for these fast swimmers.

10. Black Skirt Tetras (Gymnocorymbus ternetzi)

Black skirt tetra for a first aquarium.

Black Skirt Tetras, also known as Black Widow Tetras, are hardy, non-aggressive fish that can add a unique aesthetic to your aquarium with their distinct black and silver color pattern.

They are schooling fish and ideally should be kept in a group of 4+ individuals.

Black Skirt Tetras are extremely hardy, and make great tank mates for a variety of other peaceful fish.

Consider keeping them with mollies, neon tetras, or other colorful fish that contrast well with the black and silver palette of these tetras.

11. Harlequin Rasboras (Trigonostigma heteromorpha)

Harlequin rasbora for a first aquarium.

Harlequin Rasboras are schooling fish that have a unique black pattern adorning the sides of their bodies.

Harlequins are peaceful and look incredible in planted tanks.

They are somewhat shy fish and do best in tanks with plant cover.

A group of 4+ fish is ideal, but if you have the space (20+ gallons) consider keeping larger group of these fish because they look stunning when swimming in a school.

12. Corydoras Catfish (Corydoras spp.)

Bronze corydoras in a planted tank.
A school of Bronze corydoras (Corydoras aeneus)

Corydoras catfish, or “Cory” fish, are small, sociable freshwater fish from South America.

They have delicate little barbels that look like whiskers, so make sure you provide a smooth substrate for them.

Sand and rounded gravel substrates work well.

Corydoras are peaceful and gregarious, making them ideal for community tanks. They are a schooling species and do well in a group of 4-6 fish.

They can be somewhat nervous, so providing driftwood, live plants, and other hiding places will help them feel comfortable.

Corydoras are available in a variety of sizes, so make you are getting a species appropriate for your aquarium.

If you have a 5 or 10 gallon, then I highly recommend getting pygmy corydoras, which stay small and won’t feel cramped in smaller aquariums.

Fish I Do Not Recommend For a First Time Aquarium

Some of the most popular fish in the aquarium hobby are actually not ideal for first time aquarists.

So, let’s go over which fish I would avoid if I was setting up my first aquarium.

Goldfish (Carassius auratus)

Goldfish are not recommended for first aquariums.
Goldfish start off small, but grow rapidly if given room

Who hasn’t had a goldfish as a kid? Goldfish are beautiful, personable fish that come in a variety of different shapes and colors, but they are not an ideal fish for those just getting started with aquariums.

Why?

Goldfish need lots of space.

They are also social and prefer to be in the company of other goldfish.

This might seem surprising given that goldfish are often portrayed as thriving in bowls, but goldfish can actually reach between 6-14 inches in length, depending on the variety.

Goldfish become too large for beginners.

Goldfish kept in small bowls and tanks don’t reach these sizes because the size of their enclosure actually stunts their growth.

Stunted goldfish often have health problems, and develop bulging eyes and crooked spines because their organs keep growing while their bodies remain the same size to accommodate the size of their tank.

To properly keep a group of goldfish, a 40+ gallon tank is needed, or a pond, which is why I consider these fish to be unsuitable for most first-time aquarists.

Goldfish are also messy fish and produce large amounts of waste that turns into ammonia, which quickly becomes life-threatening in smaller tanks.

And, goldfish are cold-water fish, which means they do best at temperatures between 68-74 Fahrenheit. This rules out most tropical fish as tank mates.

So, again, unless you want to become a goldfish breeder, I suggest starting with a different fish for your first aquarium.

Oscars (Astronotus ocellatus)

Oscar fish are not recommended for first aquariums.

Like goldfish, Oscars are incredible fish full of personality.

Also, like goldfish, Oscars need lots of space.

In fact, Oscars can reach 10-12 inches in length in as little as a year!

Growing up, I had two Oscars in a 110-gallon tank, and it’s hard for me to imagine these magnificent fish having less space than that.

Basically, Oscars are amazing fish, but I don’t recommend them for a first aquarium, because that aquarium needs to be huge.

Discus (Symphysodon aequifasciatus)

Discus are not fish for beginners.

Discus are some of the most interesting and beautiful fish in the aquarium hobby (at least to me).

But, they are also surprisingly challenging fish to keep, even for veteran aquarists.

Discus require stable and pristine water conditions, any spikes in ammonia can be disastrous for these fish.

Discus are also large fish, reaching 8 inches in size fully grown.

And, they are schooling fish, which means you need multiple Discus (5+) for these fish to feel comfortable.

They are also expensive.

So, in my view, Discus fish are a terrible fish for a first aquarium; aquarists should level-up their skills as fish keepers before going on all in on Discus.

Freshwater Puffer Fish (Tetraodon spp.)

Mbuna puffers (Tetraodon mbu) can reach 26 inches (67 cm) in length

In general, puffer fish are not ideal for a first aquarium because have specialized diets and their care requirements vary greatly by species.

Some puffers require brackish water, some do not.

Some are tiny (pea puffers) and some are huge (mbuna puffer).

Some even need to have their teeth/beaks trimmed.

Overall, puffer fish require extra research and extra care (including a specialized diet) so I do not consider these fish a great choice for a first aquarium.

Conclusion

My list of the best fish for a first aquarium contains quite a few livebearers, but for good reason.

Livebearers like mollies and guppies are hardy, full of personality, and easy to breed if that’s something you want to experience.

Betta fish are also an excellent choice for a first aquarium, they have so much personality and are a personal favorite of mine.

Whatever you choose, you can’t go wrong with any of the fish on this list, just make sure you have the proper setup for each species and cycle your tank before adding fish to it.

Consider setting up a planted tank for the fish you choose, it makes the experience even more rewarding.

Check out my articles on planted tanks for beginners and the best driftwood for aquariums to learn more about what you need to get started.

Now it’s up to you, do your research and start the journey of becoming an aquarist, it might change your life.

As always, stay zen.