14 Most Colorful and Beautiful Aquarium Fish and How To Care for Them: A Complete Fact Sheet, Behavior, and Care Guide

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For many aquarists and new hobbyists, keeping an aquarium is about the aesthetic beauty the creatures – whether or coral or fish – bring to our homes.

That often means we’re looking for the most colourful tropical fish and prettiest freshwater fish around.

To help you in your search for the most stunning bright colored freshwater fish, I’ve crafted this list of the most colorful or unique looking fish I could find.

I’ve compiled basic information – like basic care instructions, temperament, and tank conditions – to help you in your decision process.

These peaceful fish, aggressive fish, or semi-aggressive fish will keep your aquariums popping with bright, vibrant colors, intriguing personalities, and interesting behaviors.

The Most Beautiful Freshwater Aquarium Fish and Saltwater Tank Fish You Can Own

To make things a little more visually organized, I’ve done my best to categorize these colorful fish color categories.

Purple Aquarium Fish

#1. Purple Dottyback

Purple Dottyback
FamilyPseudochromidae
Scientific NamePseudochromis
Other NamesStrawberry Gramma, Magenta Dottyback
Care LevelEasy
TemperamentSemi-Aggressive
DietCarnivorous
Water Conditions72 to 78-degrees Fahrenheit; pH 8.1-8.4
TypeSaltwater
Max Size2 Inches
Life Span5-7 Years
Minimum Tank Size20 Gallons
Compatible WithSemi-aggressive fish, but not other Basslets or Dottybacks

This single purple saltwater fish is my favorite for keeping as a pet.

The incredibly vivid color makes these guys fun to watch, especially against a dark aquarium background.

They do best in aquariums with plenty of live rock and hiding places and are great community fish when housed with appropriate semi-aggressive species – but not fellow Dottybacks or Basslets.

If, however, you do want multiple Purple Dottybacks, be sure to introduce them to the aquarium all at once to help curb territorial behavior that causes aggression towards each other.

They’re incredibly hardy little fish who need to be kept in aquariums with lids. They’re jumpers!

Red Aquarium Fish

#2. Lionfish

lionfish on white background
FamilyPterois
Scientific NamePteroinae
Other NamesZebrafish, Firefish, Turkeyfish, Tastyfish, Butterfly-cod
Care LevelEasy to moderate (species specific)
TemperamentAggressive
DietCarnivorous
Water Conditions72 to 78-degrees Fahrenheit; 8.1-8.4 pH
TypeSaltwater
Max Size18 Inches
Life SpanVaries by species
Minimum Tank Size50+ Gallons
Compatible WithSimilar or larger fish – will eat smaller fish

Lionfish are native to Indo-Pacific, South Pacific, Sea of Japan, and the Red Sea. However, they have migrated to other parts of the world – including Florida – where they are often considered invasive species.

They prefer the dim light of pre-dawn and evening hours for hunting – i.e. feeding times, people! – which happens to be when they blend in best with their native environments.

Lionfish are mostly solitary and not very active.

They’re generally pretty docile towards humans – in fact, I’ve not seen any real reports of aggression towards humans – but they will swiftly kill a smaller fish in a single motion.

It’s important to note that the spines on lionfish are venomous. Be careful to always wear thick gloves when the possibility of physical contact with your lionfish may occur.

#3. Flowerhorn Cichlid

flowerhorn cichlid
FamilyCichlid
Scientific NameNA
Other NamesFlowerhorn, Hua Lao Han Cichlid
Care LevelEasy
TemperamentIntelligent, extremely aggressive
DietCarnivorous
Water Conditions77 to 84-degrees Fahrenheit; pH 6.0-7.5
TypeFreshwater
Max Size10 Inches
Life Span8-10 Years
Minimum Tank Size100 Gallons
Compatible WithNone

Flowerhorn Cichlids are man-made hybrids that originated in Asia and are some of the most colorful cichlids.

They’re a stunning and unique freshwater aquarium fish that is easy to care for because, well, they just don’t need much.

The one thing he needs constantly, though, is food. It’s important to make sure you keep this guy fed at all times.

Otherwise – if you couldn’t tell from his diet – he may start eating things he shouldn’t.

He should never be housed with other fish, as he’s extremely aggressive and likely to attack the other creatures, including potential mates.

Keepers should be cautious as well, when coming in contact with them, as they may attack humans if seen as a threat.

But seriously, if you’ve ever seen these swimming around, you’ll know these are some of the coolest freshwater fish to own.

#4. Harlequin Rasbora

harlequin rasbora
FamilyCyprinidae
Scientific NameTrigonostigma heteromorpha
Other NamesRed Rasbora, Harlequin Fish, Harlequin
Care LevelEasy
TemperamentPeaceful
DietOmnivorous
Water Conditions75 to 81-degrees Fahrenheit; pH 6.5-7.5
TypeFreshwater
Max Size2 Inches
Life Span3-4 Years
Minimum Tank Size5 Gallons
Compatible WithMost fish of similar size and peaceful temperaments

Your Harlequin Rasbora should be kept in schools of at least eight of their own kind. They’re schooling fish who tend to get nervous in smaller groups.

Line your tank with dark substrate for peak coloration, and provide your rasboras with live plants, large rocks, and driftwood to imitate their natural habitat.

Make sure your rasbora get a varied diet of high-quality flakes or granules and some small live foods like artemia and daphnia.

They also could use with supplemental dietary items like freeze-fried bloodworms and tubifex worms and even some fresh veggies.

These bright freshwater fish come in a range of colors from pale pink to bright red or coppery orange.

Blue Aquarium Fish

#5. French Angelfish

french angelfish
FamilyPomacanthidae
Scientific NamePomacanthus paru
Other NamesBlack Angelfish, French Angel
Care LevelModerate
TemperamentSemi-Aggressive
DietOmnivorous
Water Conditions72 to 78-degrees Fahrenheit; pH 8.1-8.4
TypeSaltwater
Max Size15 Inches
Life Span10-15 Years
Minimum Tank Size250 Gallons
Compatible WithVaried, multiple

French Angelfish are a fairly hardy species of fish that can live a long time if properly care for.

They’re semi-aggressive and should be kept in large aquariums with lots of live rock, sponges, algae, and decorations that help it stay happier and healthier.

They’re likely to become the dominant fish in your tank, but they do mate for life if they choose a mate. Generally, speaking, though, they should be kept separate from other French Angels to keep them safe.

These pretty fish are saltwater fish but are not good candidates for reef tanks since they nip at corals and other sessile invertebrates.

#6. Regal Tang

regal tang fish
FamilyParacanthurus
Scientific NameParacanthurus Hepatus
Other NamesBlue Tang, Pacific Blue Tang, Royal Blue Tang, Hippo Tang, Palette Surgeonfish
Care LevelModerate
TemperamentNon-aggressive; semi-aggressive toward other Tangs
DietNaturally herbivorous
Water Conditions72 to 82-degrees Fahrenheit
TypeSaltwater
Max Size12 Inches
Life Span20 Years
Minimum Tank Size100 Gallons
Compatible WithMost species, except other tangs

Royal Tangs are not typically aggressive, except with each other. If you have a very large tank you can keep more than two together, as they’ll have enough space, but generally speaking, Blue Tangs should be kept with other species but not each other.

In other words, they make for great community tank fish.

Since their vibrant blue and yellow coloring makes them some of the most beautiful saltwater aquarium fish, you’ll enjoy these little “Dory” fish into your saltwater or reef aquariums.

It’s important to note that Regal Tangs need lots of swimming space. They’re also warm water lovers and herbivores, meaning they’ll eat up that algae that the warmth of the water draws.

Health note: Tangs tend to be susceptible to lateral line erosion and marine parasites, so you’ll need to carefully choose and observe your tangs for these potential illnesses.

Multicolored or Varied Color Fish

#7. Betta

colorful red and blue betta on black background
FamilyOsphronemidae/gourami
Scientific NameBetta
Other NamesSiamese Fighting Fish
Care LevelEasy
TemperamentAggressive
DietCarnivorous
Water Conditions76 to 81-degrees Fahrenheit; 6.5-7.5 pH
TypeFreshwater
Max Size3 Inches
Life Span3-7 Years
Minimum Tank Size3 Gallons
Compatible WithPeaceful non-fin nippers

Betta are some of the most colorful freshwater aquarium fish, coming in beautiful red, blue, orange, yellow, green and purple freshwater fish.

These stunning creatures are highly aggressive, though, so should always be kept separate from other bettas.

The males should also be kept in tanks that are distanced reasonably far apart to avoid jumping into other tanks for fighting. Females may be kept together if you keep at least five of them together.

And despite common aesthetic practices, betta should never be kept in a bowl. They need a bit of space to move and they always need a lid. These guys are jumpers!

Just make sure the betta can reach the top of the tank, so you may want to opt for a shallow, long aquarium.

#8. Banggai Cardinalfish

BANGGAI CARDINALFISH
FamilyApogonidae
Scientific NamePterapogon kauderni
Other NamesKaudern’s Cardinalfish, Longfin Cardinalfish
Care LevelEasy to Moderate
TemperamentNon-Aggressive
DietCarnivorous
Water Conditions75 to 82-degrees Fahrenheit; 8.1 – 8.4 pH
TypeSaltwater
Max Size3 Inches
Life Span5+ years
Minimum Tank Size30+ Gallons
Compatible WithPeaceful tankmates and mated pairs, schools in large aquariums may be possible

Banggai Cardinalfish are a peaceful species of reef fish that love the nighttime. They typically hide among coral and anemones during the daytime, so it’s recommended that you give them plenty of places to hide.

If you really want to be able to enjoy them during daylight hours, however, they can become used to being out and about during these hours with some regular encouragement and interaction – that is feeding favorite foods (like treats) during daylight hours.

Larger groups of these cool looking fishes can sometimes split into units and live in different parts of an appropriately sized aquarium.

Large groups in small aquariums, however, will have fights between them, so it’s always recommended you strictly follow the guidelines on size tanks for these sparky little fish.

Banggai Cardinalfish thrive in large, spacious reefs with loads of overhangs and nooks. They need brisk water movement and solid filtration to stay healthy and happy and prefer subdued lighting, especially if you prefer to watch these guys during daytime hours.

These fish are particularly great for nano reef aquariums, but the preferred groupings of eight or more require something like 100+ gallons or a pair should be kept in 30+ gallons. This helps to prevent them from fighting over territory.

#9. Killifish

orange killifish
FamilyAplocheilidaeCyprinodontidaeFundulidaeProfundulidaeValenciidae
Scientific NameHeterandria formosa
Other NamesNA
Care LevelEasy to Difficult (species dependent)
TemperamentPeaceful
DietCarnivorous
Water Conditions72 to 75-degrees Fahrenheit; pH 5.5 to 7
TypeFreshwater
Max Size3.5 Inches
Life Span3 months to 5 years
Minimum Tank Size20 Gallons per pair
Compatible WithCommunity tank (species dependent)

The species of Killifish you choose will greatly impact the lighting conditions your tank needs. Be sure to research this carefully, as some fish prefer anything from shade all the way to direct sunlight. Others prefer very low light.

Most Killifish require low to zero water movement, so many of the accessories that you might to have for other fish won’t work well with these little guys.

They do, however still need filters, so it’s recommended you use under gravel filters, if possible, to reduce water movement.

These cute freshwater fish are a colorful freshwater community fish that typically come in:

  • Red
  • Blue
  • Green
  • Gold
  • Orange
  • Brown
  • Silver

#10. Discus

red discus fish
FamilyCichlid
Scientific NameSymphysodon
Other NamesPompadour fish
Care LevelModerate
TemperamentPeaceful
DietCarnivorous
Water Conditions82 to 88-degrees Fahrenheit; 6-7 pH
TypeFreshwater
Max Size8 Inches
Life Span10 years
Minimum Tank Size50+ Gallons
Compatible WithNon-aggressive species

Discus are beautiful and very peaceful species of fish, and some of the most colorful freshwater fish you can safely keep in an aquarium environment.

They are very sensitive to a new environment, however, so when you bring some home, you’ll need to quarantine them for 1-2 weeks before bringing them into the main aquarium.

If possible, treat the quarantine tank with Prazipo when you introduce the discus there.

Discus naturally live in slow-moving tributaries and pools of the forest with dense tree roots, rocks, and thick vegetation. They tend to be shy, so having some of these in their home aquarium will help them feel more at ease.

They need subdued lighting and dark substrate for ultimate happiness and should be kept with other fish that are non-aggressive.

Discus fish come in green, brown, blue, and red colors.

#11. Mandarinfish

mandarin fish
FamilySynchiropus
Scientific NameSynchiropus Splendidus
Other NamesMandarin dragonet
Care LevelChallenging
TemperamentGenerally non-aggressive
DietCarnivorous
Water Conditions72 to 82-degrees Fahrenheit
TypeSaltwater
Max Size4 Inches
Life Span2-4 years
Minimum Tank Size30 Gallons per fish
Compatible WithMost species, except non-dwarf Angelfish

Just looking at these stunning fish tells you why these are some of the coolest saltwater aquarium fish ever, despite being a bit challenging to keep safe and healthy.

Mandarinfish in the wild typically eat fish eggs, snails, copepods, and small worms.

However, these are hard to come by for many folks, so you’ll want to focus on live food such as brine black worms and other small worms, and, if lucky, you may be able to introduce frozen food varieties like brine shrimp.

Mandarinfish do well in aquariums with lots of live rocks and live sands, as they eat the organisms that grow there.

Keeping Mandarinfish alive can be a challenge in a closed environment like an aquarium. They need to be trained to consume high-quality, high-protein foods since generally they eat away the copepods on the live rocks and sand reasonably quickly.

This weaning is done through an eyedropper, which many folks have noticed these most beautiful aquarium fish will wait for and suck out the shrimp out of.

Some aquarists have had some success in weaning them onto pellet food.

Mandarinfish are not able to compete with voracious eaters, so you need to be careful not to keep them with aggressive feeders.

Typically, Mandarinfish are blue or green with vibrant orange markings. Sometimes, the orange or red coloring is more dominant, specifically in the species referred to as the Red Mandarinfish.

Yellow and Orange Freshwater and Saltwater Fish for Your Aquarium

#12. Figure 8 Puffer Fish

figure 8 puffer fish
FamilyTetraodontidae
Scientific NameTetraodon biocellatus
Other NamesFigure eight puffer, Eyespot pufferfish, F8 puffer
Care LevelModerate
TemperamentSemi-aggressive fin nipper
DietCarnivorous
Water Conditions75 to 82-degrees Fahrenheit; 7.6-8.3 pH
TypeFreshwater / Brackish
Max Size3 Inches
Life Span15 years
Minimum Tank Size15 Gallons
Compatible WithLimited compatibility with other species and other puffers

Figure 8 Pufferfish are one of the most colorful varieties of puffers. Their stunning colors and unique personalities make them an interesting aquarium fish, but they don’t generally get along well with others – either puffers or other species of fish.

Figure 8 Puffers are extremely sensitive to toxins in their water, so their environment must be carefully monitored to keep them healthy, thanks to their lack of scales and gill covers.

They do best in low-end brackish water rather than straight up freshwater, but well-cared for Figure 8s have actually been reported to live as long as 18 years.

Since most brackish water fish are sold in freshwater, it’s best to make sure you use a fish-less cycling technique to prepare the tank at home.

And once your fish is comfortably adjusted into your home aquarium, they do best with a 50-percent weekly water change for ultimate health and happiness.

These fish are generally found in slowly moving or standing water in Asia and range from a yellow to green coloring.

#13. Clownfish

clownfish
FamilyPomacentridae
Scientific NameAmphiprion ocellaris
Other NamesAnemonefish
Care LevelEasy
TemperamentPeaceful, but spunky
DietOmnivorous
Water Conditions74 to 78-degrees Fahrenheit; 8.0-8.4 pH
TypeSaltwater
Max Size6 Inches
Life Span3-5 years
Minimum Tank Size20 Gallons
Compatible WithWide range of compatible tankmates

Clownfish can live alone or in groups with other clownfish. They’re a unique blend of loner and life of the party, with fairly easy-to-care-for needs, as long as their environment has everything they need.

Because of this chill attitude, they do well with other fish, especially more timid and non-aggressive fish.

They do require daily feeding to stay healthy.

While the name of these energetic little fish tell us they have that beautiful symbiotic relationship with anemones, they don’t actually require a host anemone to survive.

However, they do best with one, so be sure to research and discover which species of anemones work with the species of clownfish you bring home.

However, novice saltwater aquarists should probably put off getting clownfish until they have a bit more experience in maintaining the right environment, for the sake of those finicky anemones.

While Finding Nemo tells us that Clownfish are orange, they actually range from yellow to orange, reddish or even brownish in color.

Bonus: Prettiest Crabs to Keep at Home

#14. Halloween Moon Crab

halloween moon crab red crab
FamilyGecarcinidae
Scientific NameGecarcinus quadratus
Other NamesRed land crab, white spot crab, Halloween crab, moon crab, mouthless crab, Harlequin land crab
Care LevelModerate
TemperamentVaried
DietOmnivorous
Air TemperatureBetween 80 and 85-degrees Fahrenheit
TypeLand/Saltwater
Life Span10-12 years
Minimum Tank Size20+ Gallons
Compatible WithHappiest in pairs (one of each gender)

Halloween Moon Crabs are a quirky, colorful little crab that makes for a good pet, as long as it is well-cared for.

For the best possible life, they should be kept in opposite gender pairs and should be handled daily to help them feel safe and comfortable with human interaction.

Despite what many of the reviews and blogs say on the subject, these guys need aquariums of at least 20-gallons. They’re best housed in aquariums of 50-gallons, though, to allow for roaming, burrowing, and hiding, as they naturally do in their wild habitat.

They also need both land and saltwater areas in their habitats to stay healthy and happy.

Other Popular Colorful Fish

Some of the other most commonly kept, bright, colorful aquarium fish include:

  • Fantail Guppy
  • Dwarf Gouramis and Blue Gouramis
  • Zebra Danios
  • Neon Tetras
  • Endler’s Livebearers
  • Platy
  • Swordtail
  • Goldfish
  • Kuhli Loach
  • Cherry Barb
  • Boseman’s Rainbowfish
  • Peacock Cichlids
  • German Blue Rams
  • African Cichlids

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