21 Most Beautiful Fish in the World (For Your Aquarium)

With so much of the earth covered in water, it only makes sense that there are a lot of different water species. There are thousands of different fish in the world, but we have found a way to select the 21 most beautiful fish to keep in an aquarium.

We considered a few things when selecting these fish. Can they thrive in aquariums? Do they need other wildlife to survive? Do they always remain beautiful or do they ever change colors?

All of the fish listed below would make beautiful selections for your aquariums. They are bright, colorful, have long lifespans, and can thrive in aquariums.


21. Threadfin Butterflyfish

This fish can be up to nine inches long. It’s a white fish with beautiful chevron stripes down its side. It has dominant black markings, which stand out against the white. It does well in big fish tanks, but be aware it can become a bit territorial in a smaller tank, so do not place it in a small tank with small fish that it might want to eat.

20. Betta Fish

This is a very colorful fish also known as a “Siamese fighting fish.” They will do best in a tank with lots of other compatible, docile fish, as they can get lonely. They’re also known to overeat, so make sure to feed them only what they can safely eat in a couple of minutes. Betta fish do best in bigger tanks, and wouldn’t do well in a small tank by themselves. If placed with the wrong fish, with aggressive fish, they can get hostile.

19. Killifish

This is a very vibrant fish that needs freshwater, not saltwater. They are pretty small in size, usually only an inch or two. While none of them really look the same, the one thing they all do have is bright, vibrant colors, making them a beautiful addition to your aquarium. They do well in pairs, and you should get two if you are going to keep them in an aquarium. In pairs, they can be an aquarium with other fish.

18. Gourami

These fish can be a mixture of blue and pink, and can look like a gender reveal party of both sexes. They do a bit better in warmer water, so make sure your aquarium is heated. Males can be a bit aggressive and tend to fare better by themselves, but females can easily be kept in a tank with other fish.

17. Regal Angelfish

A striped blue and gold fish, this fish would add some great color to your aquarium. This is a large fish with a long lifespan, as it can grow to up to 10 inches and live for 15 years. It needs a very large, saltwater tank in order to thrive. This fish can thrive with reef and coral in the tank. Regal angelfish are not aggressive, and should not be kept in an aquarium with other aggressive fish as they will not be compatible.

16.  Symphysodon Discus

Some might say this is the most beautiful aquarium fish of them all, and it’s orange and white colors make it look like a creamsicle ice cream cone. This is a very peaceful fish and can live in harmony in a tank with many different types of fish. They can be picky eaters, and will not survive if you are only feeding dry, flaky food in your aquarium. These fish need fresh or frozen food to survive.

15. French Angelfish

This is a darker fish. Midnight blue, it would blend in ocean waters. Don’t be fooled, while it is dark, it is still beautiful. The yellow markings on this fish pop out in contrast to the dark blue body. These fish can be territorial, and they are quite large, growing up to 16 inches. They can live for a long time in a tank, as long as they are fed with marine algae. Don’t bother with meaty proteins like shrimp, as this fish just needs some algae to thrive. It also does not much like dry food.

14. Banggai Cardinalfish

A very beautiful, tropical fish, this fish has a silver body with black stripes. It also has white spots on its body, making it quite unique in appearance. They’re a saltwater fish, so make sure your tank is saltwater, not freshwater. If the tank is big enough, you can keep more than one fish together. These fish can survive in smaller tanks, but only by themselves.

13. Moorish Idol

A saltwater fish, this fish is shaped like a disc. Their dominant colors are black, yellow, and white. Some of these can be dull and washed out, which is a sign of mistreatment. If you are buying this fish, make sure it’s colors are nice and bright! They do well in a tank with a lot of fish, as long as none of them are aggressive. Adults won’t do well if never in a tank before with a lot of fish. It’s best to introduce this breed of fish to a tank with a lot of fish when they are at a young age.

12. Flowerhorn Cichlid

This fish has very vivid colors, but its trademark is the distinctive shape of it shed that it is named after. Be cautious, they are an aggressive fish, and will eat other fish that don’t fight back. If you plan ahead and introduce them early in their life, they can thrive in a tank with other fish. They are a freshwater fish, and can grow up to 16 inches in length.

11. Flame Angelfish

The bright red and orange bold colors of this fish make it a popular choice for aquariums. It requires a big tank, and it also likes to hide, so make sure you have a lot of objects and plants in the aquarium for it to play with. It’s a great aquarium fish, and should be the last fish that you bring to your aquarium.

10. Clownfish

Nemo! Orange and white, this fish gained in popularity after Finding Nemo. The good news is, clownfish are fairly easy to care for, as long as they don’t have a broken fin. They don’t need a big tank, and they can swim well with others. They do require a saltwater tank. Not strong swimmers, the clownfish will need some objects in the tank to hide behind and take rests when other, stronger swimmers want to go swimming by them.

9. Picasso Triggerfish

Their colors are truly remarkable, as you would expect for a fish named after Picasso. Its body can be considered neutral, as it’s usually an in color. However, there are a variety of multi-colored stripes and patterns on top of the base that make it look awesome! A must-have for your tank, this fish is pretty easy-going as long as it has a large tank with a lot of hiding places. A little bit clumsy, this fish might knock things over while it’s swimming around.

8. Lionfish

This a very beautiful saltwater fish. However, it can also be quite deadly. With spikes coming out of its body, this fish is easily recognized. The problem is, those spikes have venom, and it can be harmful to both other fish and to humans. Be very careful if you are selecting this fish for your aquarium, it might not be worth the effort, as dealing with the spikes can be quite difficult and quite dangerous.

7. German Blue Ram Fish

This is a very colorful and very small fish. It has a spiked fin, and can look a bit intimidating, but it is actually a good candidate for an aquarium, as it can thrive in small areas. It’s also a peaceful breed of fish and can tolerate swimming with a variety of different types of fish.

6. Regal Tang

This is Dory to go with Nemo from above! This bright blue fish is not as forgetful as is in the movie. They can thrive in smaller tanks and be surrounded by other fish. Water quality is important, and you’ll want to make sure your tank is cleaned regularly, else you risk Dory swimming away and getting lost! This fish can thrive with other fish, and is a great option for a beginner just starting out with aquariums.

5. Clown Triggerfish

The colors on this fish are very dramatic, making it a very popular addition to aquariums. It can be a bit of an aggressive fish, and you should choose to pair it with other large, aggressive fish who can tolerate being in the tank with this fish. Do not put this fish in a freshwater tank! It requires saltwater. And, make sure the tank is a large enough capacity.

4. Juvenile Emperor Angelfish

A saltwater fish, this fish has a bright blue body making it a very beautiful option for your aquarium. It actually has a mask on its eyes that is like a raccoon. A freshwater fish, they can thrive in a large tank with other fish. The tank needs to be at least 100 gallons in size in order for this fish to thrive. This can be an aggressive fish, so they need to have plenty of room in the tank, and be careful when introducing other fish for the first time. Do not put any fish in the tank with them that are small enough to eat. You want to feed this fish plenty of marine algae.

3. Cherry Barb

In additional to having bright colors, they also do well swimming in schools, which make them a great option for aquariums. They can withstand different temperatures and are pretty hardy, so they are a good fish for a beginner. They would do best in tanks with a lot of plants. They’re a small fish, and red from head to tail. Since they like to swim in schools, they will probably gravitate to the middle of your tank with other fish.

2. Endler’s Livebearer

A freshwater fish, this is by far one of the most beautiful options for your aquarium. Some people call this just a colorful common guppy, but this fish is more than tha. It’s also a great option because, as a small fish, it can thrive in a small tank with other fish, and handle many changing conditions. As an omnivore, it’s best to feed this fish some meaty options like brine shrimp as well as marine algae.

1. Mandarinfish

While beautiful, they can be a bit difficult to manage in an aquarium. Their bright colors make them absolutely marvelous to look at. However, their diet is challenging. They eat only live food like copepods, and they need to be trained slowly to thrive on other types of proteins. It’s very difficult to feed this type of fish in an aquarium. If you are successful, it is unlikely you would ever be able to cohabitate this fish with other fish, as the other fish would likely eat all the food before the mandarinfish had a chance to. While they are by far the most beautiful option on this list, they are also one of the most difficult to manage in an aquarium.


There are a lot of beautiful fish you can choose from for your aquarium! Take note to make sure if you have multiple fish that you are grouping together fish that can co-mingle. Some fish are more aggressive, and won’t fare well in smaller tanks with a lot of fish.

Also, be sure to pay attention to if the fish needs freshwater or saltwater, and choose accordingly. Not all fish eat the same food, so make sure you are choosing fish with similar dietary needs, and you’ll soon have a full aquarium of beautiful fish that can live for years and years!

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