What are the Best Fish for a Fish Tank

Angelfish (Pterophyllum family)

The main characteristics of the popular freshwater angelfish (Pterophyllum) are the triangular body shape and the extended flowing fins of their unique "angelic" frontal silhouette.

In fact, they are native to the slow-moving waters of the Amazon Basin in Brazil and they are a member of the Cichlidae family.

Aquarium Care for Angelfish

Body Size:

Even though freshwater angelfish are one of the best fish for a fish tank, the adults can grow up to fifteen (15) centimetres long (6 inches), twenty (20) centimetres tall (8 inches), and about ten (10) centimetres in diameter (4 inches).

Temperament and Breeding:

They are generally quite peaceful but they may become somewhat territorial when kept in large groups and when they start breeding.

Tank Size and Water Conditions:

It's best to keep angelfish in a midsize or large container (with a minimum of 20-gallon tank dimensions). They thrive best in warm (75 - 82° Fahrenheit) and slightly acidic to neutral (pH 6.5 - 7.5).

Dietary Requirements:

Freshwater angelfish are typical omnivores, meaning they will eat flakes, pellets, live, or frozen foods (e.g. bloodworms, brine shrimp). As part of their meat-based diet you can also supplement their nutrition with small aquatic crustaceans, shrimp pellets, and white worms.

Compatible Tank Mates:

As long as your aquarium is big enough, and they are not cramped together in large groups, angelfish are mostly peaceful.

Some of the most appropriate tank mates include corydoras, gouramis, and most of the tetra species (e.g. don't mix freshwater angelfish with the fin-nippers).

Pro Tip: Angelfish can be the ideal starter fish for beginners and semi-experienced fishkeepers. You can expect them to thrive quite happily if you provide them with a well-maintained tank with some live plants.

Betta Fish (Betta splendens)

Anyone who has been learning how to keep fish would also know that the common name for bettas is the Siamese fighting fish. Thus, being fiercely territorial is the reason for the funny fish names.

They are one of the most popular freshwater fish to keep in a tank, mostly due to the intense colouring of their body and fins. But, you should only keep a single male in the same aquarium due to their aggressive nature towards each other.

Aquarium Care for Siamese Fighting Fish

Body Size:

Excluding the tail, it would be rare for a male adult betta to grow more than seven (7) centimetres long (3 inches). The females tend to be a tiny bit smaller than the males.

Temperament and Breeding:

A single male, or a small group of females (e.g. a "sorority" tank), will generally be non aggressive. But, they will fight to the death if you put more than one male in the same container.

Betta fish only require a few inches of water to breed because the male builds the bubble nest close to the surface.

Even so, the conditions would need to be optimum for a male to successfully lure a female to his nest and induce her to lay eggs.

Tank Size and Water Conditions:

If you're a beginner, you should find it quite easy to keep bettas in a small or midsize aquarium. Although they can tolerate cooler water temperatures, they thrive better in warm water (76 - 85° Fahrenheit) with gentle filtration (pH 6.8 - 7.5).

Dietary Requirements:

Betta fish are carnivores so they need a diet packed with protein. They will eat betta flakes, pellets, live, or frozen fish foods (e.g. bloodworms, crabs, brine shrimp).

You can also supplement their meat-based diet with tiny marine invertebrates like shrimp pellets, insects, and insect larvae.

Compatible Tank Mates:

Even though bettas are known for attacking almost anything they can catch, they will tolerate some limited companionship with ghost shrimp (Thalassinidea), mystery snails (Pomacea Bridgesii), African dwarf frogs Hymenochirus Boettgeri), corydora catfish, and marimo moss balls (Aegagropila Linnaei).

Pro Tip: The average lifespan of the Siamese fighting fish is three (3) years when kept in captivity. As a consequence of that, a solitary betta fish is the ideal pet to keep in a small desktop aquarium (e.g. with 5-gallon fish tank dimensions).

Corydora Catfish (Callichthyidae)

In fact, there are more than 170 documented corydoras and most of them are typical bottom-feeders that spend most of the day cleaning up leftover food scraps.

The playful behaviour and general hardy nature of cory catfish is the primary reason why aquarists like to keep these scavengers in community aquariums.

Aquarium Care for Corydoras

Body Size:

Depending on the species, most of the corydoras grow between three (3) and seven (7) centimetres long (1 to 3 inches). The females tend to be a tiny bit bigger than the males.

Temperament and Breeding:

Because they are mostly a shoaling fish, it's better to keep these small catfishes in groups of at least five (5) members.

It's not uncommon for hobbyists to simulate a rain storm to induce spawning. Hence, feed them a rich diet and create a temperature drop (partial water change) to encourage them to start breeding.

Tank Size and Water Conditions:

Even absolute beginners should find it easy to keep cory catfish in a midsize aquarium (e.g. minimum of 10-gallon tank dimensions).

Although they can tolerate cooler water temperatures, they thrive better in slightly warmer water (72 - 78° Fahrenheit) with gentle filtration (pH 6.5 - 7.5).

Dietary Requirements:

Catfish are omnivores that will eat sinking pellets (e.g. Aqueon® bottom feeder tablets) and algae wafers (rounds) with live or frozen aquarium fish food as an occasional supplement.

Compatible Tank Mates:

If you want to encourage companionship for your corydoras try mixing them with guppies, gouramis, and tetras. They also get along great with most of the larger sea snail species (e.g. mystery snails).

Pro Tip: Catfish are active bottom-dwellers that are enjoyable to watch when they forage for food in the sandy substrate.

Goldfish (Carassius auratus)

Some of the most inappropriate fish names that scientists created in the past do not include the goldfish.

Why?

Well it's gold coloured and it's a fish! If you're thinking about keeping fish as a hobby, most of the common goldfish species will be a good choice.

They are hardy and available for purchase in a number of interesting shapes and fin types, especially the comet-tailed goldfish, fantails, oranda, shubunkins, and the "king of goldfish" the ranchus.

Aquarium Care for Goldfish

Body Size:

The size differs between the various breeds. But the average size of common goldfishes kept in captivity will be between twelve (12) centimetres (4 inches) and twenty two (22) centimetres (8 inches).

Temperament and Breeding:

It's fair to call goldfish peaceful pets. Even so, it's worth pointing out that most of them are messy eaters so you will need a good filtration system.

Even though most goldfish species will spawn in home aquariums they are typical egg scatterers.

In other words, the adults will completely abandon the eggs after the female has laid them.

If you are planning on breeding goldfish, you will see the sticky eggs clinging to plants and other objects. It would be best to move the eggs to a separate tank to stop the adults (and any other fish in the aquarium) from eating them. Goldfish eggs usually hatch within 72 hours.

Tank Size and Water Conditions:

Even a solitary goldfish is going to appreciate a lot of space - not a small glass bowl. Furthermore, having a high waste output and a high oxygen demand means they will need efficient filtration.

Thus, you should consider the general size of a rectangular 20 gallon aquarium as being the minimum. We also suggest adding at least ten extra gallons of volume per additional fish.

Goldfish can tolerate cooler water temperatures and they should do well in an environment between 65 and 75° Fahrenheit with strong filtration (pH 7.0 - 7.8).

Dietary Requirements:

In the wild, the omnivorous species feed on a healthy variety of crustaceans, insects, and plant matter, like hornwort weed.

In a captive environment, they should get a high-quality diet from flakes, pellets, granules, vegetables, and the occasional protein treat.

Compatible Tank Mates:

Apart from the fin nipper fish, such as tiger barbs and dwarf gouramis, goldfish tend to be tolerant with the majority of tank mates that are similar in size and temperament - including other goldfish.

Pro Tip: The common goldfish has always been a popular aquarium fish for beginners to start fishkeeping for a hobby. In fact, give them the proper fish care that they deserve and your golden fish pet could live for more than twenty (20) years.

Guppy (Poecilia reticulata)

Setting up an aquarium with dozens of fancy colourful guppy fish is a delightful sight. Guppies are small, relatively easy to breed - even in a modest tank - and they are one of the favourite fish for beginners to keep as pets.

Aquarium Care for Guppies

Body Size:

One of the smallest tropical fish species is the male guppy. It's rare for males to grow bigger than three (3) centimetres (1.5 inches) and the average size of female guppies is about six (6) centimetres (2.5 inches).

Temperament and Breeding:

It's true to say that most fishkeeping hobbyists enjoy watching the relentless swimming behaviour of energetic guppy fish.

They have a gregarious nature and almost all of the various strains display some vivid colouration and body patterns.

But...

Being a typical livebearer means the females give birth to live fry.

So, if you're new to taking care of fish in a home aquarium, you should be aware that guppies reproduce often. Put another way, you should be prepared to provide a loving home for lots of hungry babies.

Tank Size and Water Conditions:

You can keep a few in small aquarium starter kits (e.g. Top Fin® fish tanks). But, making the most of 10-gallon tank dimensions is going to be better for a collection of guppies.

Guppies prefer warm water, (72 - 78° Fahrenheit) especially during the breeding season. Water conditions should be leaning toward the hard side (pH 6.8 - 7.8).

Dietary Requirements:

Like most tropical fish omnivores, ravenous guppy fish will enjoy eating high-quality flakes, pellets, and an occasional freeze-dried or frozen food supplement.

It's better to vary their diet as much as possible with some micro invertebrates (e.g. aquatic insect larvae, crustaceans, brine shrimp).

Compatible Tank Mates:

As a general rule of thumb, you can mix guppies with most of the peaceful non-carnivorous fish. Typical examples include corydoras, mollies, tetras, and shrimps. But it's advisable not to put them with the fin nipper fish (e.g. tiger barbs).

Pro Tip: Guppies have been considered as one of the classic aquarium species for decades. Nowadays, they are also selectively bred to produce various fin and specific colour strains.

Harlequin Rasbora (Trigonostigma heteromorpha)

Rasboras are small schooling fish that can be a great addition to freshwater planted tanks. Their distinctive reddish-orange body is offset with a black triangular wedge-patterned patch that runs from the mid-section to the tail.

Aquarium Care for Harlequin Rasboras

Body Size:

Even after they reach full maturity, it's rare for harlequin rasboras to grow longer than five (5) centimetres (2 inches) in a captive environment.

Temperament and Breeding:

Because they are peaceful and enjoy being around others, we recommend keeping rasboras in small groups of at least six (6) members.

Female harlequin rasboras (Trigonostigma heteromorpha) are egg layers. Thus, keep watch for eggs being stuck to the underside of plant leaves if you're keeping male and females in the same tank.

Tank Size and Water Conditions:

Even though it's acceptable to keep harlequin fish in a 10 gallon setup, they will appreciate the extra space and thrive much better in a 20 gallon tank (75 litres).

Aim to have the water temperature ranging between 72 and 80 Fahrenheit with slightly acidic pH (5.5 to 7.0).

Dietary Requirements:

Being typical omnivores means rasboras will eat most of the common tropical fish food products available at reputable stockists. A nutritional diet should include high-quality flakes, pellets, and an occasional treat of bloodworms or brine shrimps.

Compatible Tank Mates:

Trigonostigma heteromorpha are definitely not an aggressive species, but they will be lively and active if they have space to swim in the top half of the tank.

Some of the best tank companions for rasboras include corydoras (catfish), guppy fish, platies, and neon tetras.

Pro Tip: Harlequin rasboras are in fact native to the freshwater streams and watercourses of peat swamp forests in parts of Malaysia, Singapore, southern Thailand, and Sumatra.

3 Popular Rasboras for Aquarium

1. Chili rasbora (Boraras brigittae) are good company for the best freshwater aquarium fish combination for beginners. They are small (around 3 centimetres long) with a colourful appearance. So, give chili rasboras an aquarium setting that mimics their natural swamp-like habitat, feed them a good mix of pellets, flakes, and frozen food, and they could live for up to eight (8) years.
2. Lambchop rasbora (Trigonostigma espei) is one of the funny fish names given to a species that has a dark band (shaped like a lamb chop) on its body. In the wild, the species is predominantly found in parts of Cambodia, Thailand, and on the island of Phú Quốc in Vietnam.
3. Rummy nose rasbora (Sawbwa resplendens) is a worthy candidate for being the most beautiful small fish kept in a freshwater aquarium. If you can source them from a reputable stockist, a small group of rummynose rasboras always look stunning in planted tanks.

Molly (Poeciliidae)

Despite being slightly larger and more robust, mollies have similar characteristics and fish care needs to guppies.

Hence, they are hardy livebearers that tend to get along fine in small groups when they're kept in slightly brackish water.

Molly fish are active and social freshwater aquarium fish and they are available in various body colours, sizes, and fin shapes.

Aquarium Care for Mollies

Body Size:

Most of the common molly species will not grow bigger than twelve (12) centimetres long (5 inches). Even so, it's not uncommon for some experienced aquarists to have sailfin molly (Poecilia latipinna) specimens measuring fifteen (15) centimetres long (6 inches).

Temperament and Breeding:

For the most part, mollies are active but social and peaceful with other fishes. If your tank is big enough, it's best to keep them in small groups (e.g. one male for every three females).

Like guppies, these livebearers reproduce often so prepare for lots of fry!

Tank Size and Water Conditions:

Try to keep your mollies in a 20 gallon fish tank or bigger because they like a lot of empty space to swim around.

They will tolerate some ranges in temperature but the ideal setup for molly fish is a range between 72 - 82° Fahrenheit with hard to brackish water (pH 7.0 - 8.5).

Dietary Requirements:

Most mollies are herbivores that prefer to feed on algae-based foods. Typical examples include Aqueon Pro Herbivore pellets with occasional protein treats (brine shrimp, bloodworms).

Compatible Tank Mates:

Besides guppies and platies, molly fish also get along with corydoras (catfish), tetras, and other peaceful fish of a similar size.

Pro Tip: These low-maintenance tropical fish are one of the easiest fish species to keep in an aquarium and they will provide you with a constant source of enjoyment.

Neon Tetra (Paracheirodon innesi)

Adding a group of neon tetras to any peaceful community tank is a good choice. They are small with bright colours of luminous blue and red stripes that shimmer - especially under LED lighting.

Aquarium Care for Neon Tetras

Body Size:

In general, you shouldn't expect any adult neon tetras to grow bigger than four (4) centimetres long (1.5 inches).

Temperament and Breeding:

Most of the tetra species are peaceful schooling fish. So, you can keep them in groups of mixed genders with at least six (6) in the collection (more than 10 is even better).

Many aquarists like to breed neon tetras in a captive environment. However, these egg layers tend to eat their own eggs so you may need to set up a separate tank.

Tank Size and Water Conditions:

A container that holds a minimum of forty litres (e.g. 10-gallon tank dimensions) is good enough for small schools. The ideal temperature is something between 72 and 78° Fahrenheit with soft water (pH 6.0 - 7.0).

Dietary Requirements:

Being typical omnivores means these tiny tetras enjoy a combination of plant and animal matter. You can feed them fine flake food (e.g. Aqueon Tropical Flakes), shrimp pellets, small granules, and an occasional treat with frozen brine shrimp (or daphnia), and freeze-dried bloodworms.

Compatible Tank Mates:

You shouldn't have any major conflicts if you mix neon tetras with small corydoras, guppies, and mollies. But, it's always best to avoid putting them in a tank that contains any extra large or aggressive species.

Pro Tip: Set up a healthy planted aquarium, add some dim lighting and some dark coloured substrate material, and you will enhance the unmistakable vivid colouration of neon tetras.

Ocellaris Clownfish (Amphiprion ocellaris)

If you enjoy keeping saltwater tropical fish for a hobby you might know the Ocellaris clownfish as the false percula clownfish. No matter what you call them, they are one of the favoured beginner-friendly saltwater fishes to keep as pets.

However, clownfishes are even more famous for their bright orange coloured body, broad white bands, and their symbiotic relationship with sea anemones (Actiniaria) in tropical coral reef ecosystems.

Aquarium Care for Clownfish

Body Size:

It would be very rare for a fully matured Ocellaris clownfish to grow longer than eleven (11) centimetres (4 inches).

Temperament and Breeding:

By and large, clownfish are quite passive. But, if you keep them in large groups you will find them to be more territorial in nature.

Breeding clownfish in an aquarium can be a somewhat challenging experience for beginners.

Tank Size and Water Conditions:

Clownfish are saltwater fish so you'll need to set up a marine tank with an appropriate filtration system.

The general dimensions of a 20 gallon fish tank should suffice for a pair. Then, aim for an average water temperature of 74 to 78° Fahrenheit and a salinity of pH: 8.0 to 8.4 (1.020-1.025 Specific Gravity).

Dietary Requirements:

In the wild, these omnivorous vertebrates typically feed on algae, zooplankton, and small bottom-dwelling invertebrates. In a captive environment, they should be fed with marine flakes, pellets, and a mix of frozen and live foods (e.g. brine shrimp, mysis shrimp).

Compatible Tank Mates:

Generally, Ocellaris clownfish will be harmonious with blenny fish, firefish gobies, and most other species of peaceful reef fish.

Pro Tip: It's not required to have an anemone for clownfish. Even though they can thrive without a living sea anemone, the bubble-tip anemone (Entacmaea quadricolor) would be the best choice if you're going to introduce one to your marine aquarium setup.

Platy Fish (Xiphophorus)

If you want to take care of a beginner-friendly livebearer, the platy fish is one of the easiest to keep in a modest aquarium.

Not only are they peaceful and colourful, but being low-maintenance means they are also a good choice for most community tanks.

Aquarium Care for Platies

Body Size:

Unless you're keeping dwarf platies, they should grow no bigger than seven (7) centimetres (less than 3 inches long).

Temperament and Breeding:

Platies are peaceful and social. Hence, you should have no problem keeping them in groups of three or more.

Mixing male and female livebearers is likely to reward you with lots of platy fish babies.

Tank Size and Water Conditions:

If you're only going to keep a handful of platies a 10 gallon aquarium should be fine. They do not enjoy cold environments so try setting up the water temperature to something between 70 and 80° Fahrenheit with moderately hard potential of hydrogen (pH 7.0 - 8.2).

Dietary Requirements:

Being omnivorous means they will eat a combination of freeze-dried foods, flakes, and pellets. You could also try them with an occasional frozen delicacy of bloodworms or brine shrimp.

Compatible Tank Mates:

You shouldn't have any major fights mixing platy fish with small corydoras, guppies, and mollies. But, it's always better to avoid putting them in a tank that contains any extra large or aggressive species.

Pro Tip: Check out our fishkeeping guide for children and see how it can be an entertaining, educational, and valuable lesson about the responsibilities needed to take care of animals.

Red-tailed Black Shark (Epalzeorhynchos bicolor)

Even though red tail sharks and rainbow sharks (Epalzeorhynchos frenatum) share similar appearance and behavioural patterns with the true shark phylum, they are both a species of freshwater carp (Cyprinidae).

Still, the sleek elongated black body and bright red tail is the main reason why aquarists with intermediate pet-keeping experience like to keep a single specimen in their setup.

Aquarium Care for Red-tailed Black Sharks

Body Size:

The small and streamlined juveniles tend to develop a deeper body with a rounded midsection as they get older.

Even so, it is rare for fully matured red-tailed black sharks to grow much longer than sixteen centimetres (6 inches).

Temperament and Breeding:

Besides being somewhat semi-aggressive, the territorial nature of red tailed sharks is the main reason for keeping one on its own or with a few of the small "fast-moving" species.

Official records suggest males and females live for at least five (5) years - even in captivity.

Nonetheless, their intolerant temperament (even among mating couples) makes them difficult to breed in an aquarium environment.

Tank Size and Water Conditions:

If you're keeping a red-tailed black shark, it's better to have an elongated rectangular shaped aquarium (so they can swim along the bottom and to reduce aggression) with a strong lid (to prevent jumping).

In general, the dimensions of a 100 gallon tank may seem excessive, but a container this size would give them lots of space to establish their territory.

Aim for a temperature between 72 and 79° Fahrenheit with a fairly neutral pH between 6.5 and 7.5 water hardness.

Dietary Requirements:

Even though these hungry omnivores will eat different types of live, frozen, or granular fish food products, they need a diet that is rich in algae (e.g. Hikari algae wafers and pellets).

Compatible Tank Mates:

The list of suitable tank mates for red tail sharks is a small one. However, they tend to get on better with fish that occupy the top of the tank, such as freshwater angelfish, barbs, danios, rainbowfish, and large tetras.

Pro Tip: Despite being one of the common aquarium fish kept by beginners, red-tailed black sharks can be extremely territorial. In fact, it is rare for them to get along with any of the slow-moving, bottom-dwellers (e.g. corydora catfish) and even their own species.

Zebrafish (Danio rerio)

Zebra danios, also called zebrafish, are small, active, and hardy freshwater fish. The key feature of danios is their striking horizontal stripes - hence the funny fish names relating to zebras.

They are resilient and speedy - darting around the tank. Zebrafish are an excellent choice for fishkeeping beginners with a small community aquarium.

Aquarium Care for Zebra Danios

Body Size:

Zebrafish (Danio rerio) should not grow bigger than five (5) centimetres (about 2 inches long) in a captive environment. That being said, official records of the longest zebrafish show one growing to 6.4 centimetres (2.5 inches).

Temperament and Breeding:

Zebra danios are peaceful and social. Hence, you should have no problem keeping them in groups of six or more.

Breeding zebrafish in an aquarium can be a somewhat challenging experience for beginners.

Tank Size and Water Conditions:

Being active swimmers means they enjoy swimming in open spaces. Thus, the dimensions of a 20 gallon aquarium is better if you will be keeping big size schools.

Danios can tolerate cooler water temperatures (64 to 78 Fahrenheit) and they prefer soft to moderately hard potential of hydrogen (pH 6.5 to 7.5).

Dietary Requirements:

Being omnivorous means they will eat a combination of freeze-dried fish foods, flakes, and pellets. You can also try them with an occasional frozen delicacy of bloodworms or brine shrimp.

Compatible Tank Mates:

The best companions for zebrafish are corydoras, guppies, and mollies. But, zebra danios are known to nip the fins of some species so it's best not to mix them with slow-moving long-finned species.

Pro Tip: Zebra fish are popular aquarium fish for beginners because they are low maintenance. Besides that, danios are a lot of fun to watch and a nice addition to any lively tank. With ideal conditions, your zebrafish could have a lifespan of up to five (5) years when kept in captivity.