Best Fish For A 55-Gallon Tank – 10 Awesome Species

    Best Fish For A 55-Gallon Tank

    A 55-gallon fish tank will allow you to get creative with lots of small fish or go after the bigger species. The best fish for a 55-gallon tank is not universal. Firstly, they should appeal to you, and you should be able to look at them and say, “yes, I want you as my companion” – that sort of thing. You create an emotional bond with your pets along the way – don’t deny it!

    Secondly, you need to make sure you have the time and the inclination to care for those little aquatic creatures. Some of them require a greater care level than others, so choose wisely because it’s also their life at stake.

    Following these considerations, we’ve compiled a list of 10 best fish for a 55-gallon tank, both large and small, both saltwater and freshwater, and tried to pair them with other tank mates and invertebrates for the perfect aquarium. Let’s begin!

    Cichlids (Cichlidae)

    Texas Cichlid (Erichthys cyanoguttatus)

    The Cichlid is a colorful fish that can be aggressive at times and prove a little challenging when it comes to caring for them. However, they’re very popular in the fishkeeping industries due to their gorgeous appearance. Are they the best fish for a 55-gallon tank? Let’s see!

    • Care Level: Intermediate
    • Temperament: Aggressive
    • Diet: Species Dependent
    • Water temperature: 24 °C to29 °C (75 °F to 85 °F)
    • Size: 3-15 inches
    • Family: Cichlidae
    • Lifespan: Up to 20 Years (Depending on the species)

     The Cichlid Appearance

    There are more than 1600 species of Cichlid, each with a unique appearance. The African Cichlid are some of the most popular. For example, the Haplochromis genus contains piscivorous species with long torpedo-like, silver, or grey bodies.

    For more vivid colors, there is also the Peacock Cichlid, which can get to 4-6 inches long; then, there are the Mbunas with insane color patterns. One of the most famous is the Zebra Cichlid with some emblematic stripes you might never forget.

    Cichlid Temperament

    Most of them are quite aggressive. They like to claim their territory and won’t let other fish swim too close.

    However, this doesn’t mean they’re impossible to keep. You’ll just need a suitable tank and the right tank mates.

    They’re scavengers by nature, so most of the time, when they’re not locking lips in a fight, or part of the mating ritual, they’ll be digging for food through the substrate. Make sure that all the decorations in the 55-gallon tank are properly installed and cannot be knocked down too easily.

    Cichlid Tank Mates

    To be safe, you should keep one species on its own. However, there are solutions. You can choose another species that love to dwell at the bottom of the tank so they won’t cross paths with the cichlids who love free swimming.

    Moreover, make sure you choose a similar-sized fish that also boats an aggressive temperament. You could go for clown loaches or red tail sharks. You could also pair them with African catfish, which are fast, large, and can stand up for themselves.

    Pearl Gourami (Trichopodus leerii)

    Pearl Gourami

    Native to Southeast Asia, this Gourami species is much-appreciated for the pearl-like pattern that covers its body. It looks quite amazing.

    • Care Level: Medium
    • Temperament: Peaceful
    • Diet: Omnivorous
    • Water temperature: 24 °C to29 °C (75 °F to 85 °F)
    • Size: 4-5 inches
    • Family: Osphronemidae
    • Lifespan: Up to 5 Years

    Pearl Gourami Appearance

    They’re beautiful; that’s an undisputed fact. Their entire body is covered in pear-like silver spots, with a black bar running along their side for a plus of character.

    Their fins are wide and large but incredibly thin, giving them an elegant poise. When they reach maturity, the males will develop a red breast that turns brighter every time they’re mating, making them more beautiful even.

    Pearl Gourami Temperament

    Pearl Gouramis will get along beautifully with other gourami species. They spend most of the time in the mid to upper levels of the tank. They are peaceful most of the time.

    During spawning, the males will get aggressive, though. They won’t let anyone approach their females or their nest.

    Pearl Gourami Tank Mates

    The Pearl Gouramis are good community fish. They get along well with other Gourami, but if you want more diversity, you could pair them with some small and peaceful species, such as the pearl danio or neon tetras.

    You can also go for larger species, as long as they’re not aggressive and very territorial. Loaches and catfish would do because they spend most of their time at the bottom of the tank.

    As a rule, avoid the overactive and much larger fish.

    Plecostomus (Hypostomus)

    Leopard Pleco (Glyptoperichthys gibbiceps)
    Leopard Pleco (Glyptoperichthys gibbiceps)

    Since we’re talking about the best fish for a 55-gallon tank, let’s talk about some really large species, like the Plecostomus ones; there are about 150 different species discovered so far, so you’ve got a lot to choose from.

    • Care Level: Medium
    • Temperament: Peaceful
    • Diet: Omnivorous
    • Water temperature: 22 °C to30 °C (72 °F to 86 °F)
    • Size: Up to 24 inches
    • Family: Loricariidae
    • Lifespan: 10-15 Years

    Plecostomus Appearance

    The great majority of Plecos have an elongated brown body, with large plates made of bone to cover it for protection. They could grow to about 24 inches in length in the wild, but in an aquarium, they might stay around 15 inches.

    The dorsal, pectoral, and tail fins are very well-developed, while the head is large, with small eyes and a big mouth. Their eyes are covered by a membrane that allows them to control the amount of light.

    Plecostomus Temperament

    One species called Hypostomus plecostomus is especially known for its big suckermouth, which it uses to attach to surfaces and feed on algae, and other aquatic plants.

    They’re usually bought when they’re small and young and are revered for their ability to clean algae from fish tanks.

    They’re mostly nocturnal beings. During the daytime, they’ll be hiding. During the night, they like roaming at the bottom of the tank, cleaning up the algae stuck there.

    However, please note that they are omnivores, and you should not let them feed only on algae.

    Plecostomus Tank Mates

    As youngsters, they are quite peaceful and can be kept in community tanks. They will get along with Cichlids, Tetras, Gouramies, and other types of peaceful community fish. However, they will quickly outgrow other fish in the tank, so they should be kept in their tank when they reach maturity.

    Kuhli Loach (Pangio kuhlii)

    Pangio kuhlii

    Originating from Indonesia and the Malay Peninsula, the Kuhli Loach is a nocturnal, snake-like, shy fish that likes to hide at the bottom of the aquarium.

    • Care Level: Medium
    • Temperament: Peaceful
    • Diet: Omnivorous
    • Water temperature: 23 °C to30 °C (73 °F to 86 °F)
    • Size: 4 inches
    • Family: Cobitidae
    • Lifespan: 10 Years

    Kuhli Loach Appearance

    Looking like an eel, the Kuhli Loach has a couple of pinkish vertical bars on their body, with some very small scales that do not cover their head, though. This means they could get diseases quite easily.

    The eyes are covered by transparent skin, and they have 4 pairs of barbels around the mouth and a dorsal fin that starts beyond the middle of their body.

    Kuhli Loach Temperament

    They are very peaceful and shy creatures, although they like some companions around. They are scavengers, spending their night near the bed of the aquarium, digging for food. Since they’re nocturnal creatures, so you won’t see them much during the day.

    Kuhli Loach Tank Mates

    I have an entire post dedicated to Kuhli Loach Tank Mates; click here to check it out! Peaceful and shy, they are best-kept with others sharing this temperament. They will get along just fine with Danios, Rasboras, Tetras, or Gouramis. Just don’t put them in the same aquarium with snails, as they’ll try to eat the snails.

     Puffer Fish (Tetraodontidae)

    Tetraodon mbu
    Mbu Pufferfish (Tetraodon mbu)

    This chubby cute fish might prove challenging to care for but rewarding at the same time. Some of these species possess some dangerous venom, but not to worry, they cannot harm you. With a little love, they might become your best companions.

    • Care Level: Advanced
    • Temperament: Aggressive
    • Diet: Omnivorous
    • Water temperature: 23 °C to 26 °C (74 °F to 78 °F)
    • Size: 1- 24 inches
    • Family: Tetraodontidae
    • Lifespan: 10 Years

    Puffer Fish Appearance

    There are some 150 species, maybe more, in the world, and most of them live in saltwater. Depending on the species, they are grey, with some cream or green based color.

    They are quite chubby-looking; their jaws have 4 large teeth covered by full lips that they use to test if the food in front of them is “worth it”.

    These “puffers” have a way of puffing themselves up when they feel threatened, and the bodies are covered with spikes that become visible when they inflate.  

    Puffer Fish Temperament

    They are aggressive fish and protect their territory with extreme prejudice. Puffers are predators and can employ many hunting techniques. They are also fin-nippers and might spit water over the substrate to uncover their hidden prey. There have been some stories that they could spit water at you from the surface if you don’t feed them. Now, take that with a bit of salt.

    They possess a deadly venom called tetrodotoxin, as a defense mechanism. However, they do not produce that directly, but they have learned how to gather bacteria to produce it for them in the wild. So in a tank, that won’t happen.

    Puffer Tank Mates

    When they are little, they can act as very good community fish, but they will become very aggressive and territorial as they reach adulthood. They are best kept alone. However, you can keep small groups of puffers in your aquarium, but don’t try anything else.

    Oscar Fish (Astronotus ocellatus)

    Oscar fish (Astronotus ocellatus) swimming underwater

    Oscar, “the fish,” is a brave contender for the accolade of the best fish for a 55-gallon tank.  Shall we have a closer look?

    • Care Level: Moderate
    • Temperament: Aggressive
    • Diet: Omnivorous
    • Water temperature: 23 °C to 27 °C (74 °F to 81 °F)
    • Size: Up to 12 inches
    • Family: Cichlidae
    • Lifespan: Up to 20 Years

    Oscar Appearance

    There are a lot of varieties of Oscar fish. They grow to be quite large, and they do it quickly. They can reach their full-grown state in a month or so.

    Their body is oval-shaped, with the dorsal and anal fins extending along their body all the way to the caudal fin and then in a fan at the rear. They’re monomorphic species, so you won’t be able to really tell who’s a he and who’s a she.

    As for color, they’re usually a combination of black and orange, with some nice splotches all over their bodies.

    Oscar Temperament

    Native to Brazil, Ecuador, and Colombia, the Oscar fish are very popular aquarium fish, but they’re quite difficult to care for. They boast very aggressive and territorial behavior, so you’ll have a hard time handling them.

    The Oscars are very whimsical creatures, but they can live up to 20 years if they are well-cared for. They will spend most of their time swimming in the mid-levels of the tank and only head to the bed of the aquarium in search of food.

    They would easily attack other fish if they cross their territory, so it is very important what tank mates you choose for them.

    Oscar Tank Mates

    They’re really beautiful creatures, so the first and best choice is to keep them alone in an Oscar-only tank.

    However, if you were thinking about a community, then you could take some chances with other large and passive fish species, like Arowanas, or Cichlids, who can hold their own in a fight.

    Do not even think about some other small fish species because you won’t get to look at them for long.

    Cherry Barb (Puntius titteya)

    Cherry Barb, puntius titteya, Aquarium Fishes

    Who said that the best fish for a 55-gallon tank should be big? Why not a lot of colorful Cherry Barbs to liven up the aquarium?

    • Care Level: Easy
    • Temperament: Peaceful
    • Diet: Omnivorous
    • Water temperature: 22 °C to 27 °C (73 °F to 81 °F)
    • Size: 1-2 Inches
    • Family: Cyprinidae
    • Lifespan: 5-6 Years

    Cherry Barb Appearance

    These slender cute little fish have elongated bodies with a lateral stripe from head to tail. The males are usually cherry-red, while the females are more on the white side, with a browner lateral line.

    However, both males and females could add a beautiful patch of color to any aquarium. There is also an albino variant of this fish as a result of genetic selection.

    Cherry Barb Temperament

    The Cherry Barbs will display a schooling behavior, making your aquarium a swirling fountain of color and happiness.

    Deeply social creatures, The Cherry Barbs feel good when they have a lot of fellows around. It makes them feel safe and protected in a big community. Otherwise, they might shy away. If you fall in love with them at first sight, no one is to blame you. Just make sure that you keep a 1:2 male-to-female ratio in the tank for when spawning, males tend to harass females, which could lead to nasty health complications.

    Cherry Barb Tank Mates

    The Cherry Barbs are peaceful creatures and should share the aquarium with fish that are also peaceful, like Glass Catfish, Tetras, Danios. If you want to populate the 55-gallon tank with other invertebrates and or shrimp, go ahead and add some Cherry Shrimp or Mystery Snails. They’ll get along just fine.

    Clownfish (Amphiprioninae)

    Clownfish (Amphiprion ocellaris)

    Ever thought that Nemo could be the best fish for a 55-gallon tank? Or at least, ever thought about having him as a friend? You could, because clownfish are quite easy to keep, have simple diets, and are cute.

    • Care Level: Easy
    • Temperament: Peaceful
    • Diet: Omnivorous
    • Water temperature: 23 °C to 26 °C (74 °F to 79 °F)
    • Size: Up to 4 Inches
    • Family: Pomacentridae
    • Lifespan: 6 Years

    Clownfish Appearance

    As if you needed another description of how our dear Nemo from Finding Nemo looks like… Nevertheless, we’ll do our job.  Clownfish have a rounded caudal fin, which doesn’t help them much when it comes to swimming.

    All their fins and stripes are outlined in black making them more recognizable. They usually have three white stripes on their long bodies and a dip in their dorsal fin.

    Clownfish Temperament

    Clownfish are peaceful with their kind but could get quite aggressive if they are in the same tank with another Clownfish species. That might sound weird; they probably still have some “unresolved” family issues.

    Anyways, leaving jokes aside, they are incredible and adorable fish with a very interesting relationship with certain kinds of Anemone. They are resistant to the toxins of the Anemones so that they can live together in peace. It also helps them to hide together, since they’re not very good swimmers.

    Clownfish Tank Mates

    In the wild, they like living with other reef fish. They are quite adaptable to large communities or small tanks. They have an almost symbiotic relationship with Anemones, so you could pair them that way.

    Clownfish could also get along with other small, peaceful fish such as Damselfish, Wrasses, Dartfish.

    Mandarin Fish (Synchiropus splendidus)

    Synchiropus splendidus

    The mandarin fish or mandarin dragonet is one of the most fascinating fish you could ever get for your 55-gallon tank. Once you lay eyes on one, you’ll most probably never look back. Let’s take a look.

    • Care Level: Moderate
    • Temperament: Mostly Peaceful
    • Diet: Carnivore
    • Water temperature: 22 °C to 26 °C (72 °F to 78 °F)
    • Size: Up to 3 Inches
    • Family: Callionymidae
    • Lifespan: Up to 5 years

    Mandarin Fish Appearance

    The Mandarin is absolutely gorgeous. Their large pelvic fins give you the impression that they are walking across the substrate. They have large red eyes with big, black, and deep pupils.

    Their lack of scales is compensated by a toxin they secrete to protect against any predators. As for the colors, well, they’re a wonder. There are a couple of varieties. The green and red mandarin dragonets are totally amazing with some beautiful stripes and patterns that seem like the artwork of a romantic painter.

    Mandarin Fish Temperament

    The Mandarin Fish like to take their time. They dwell at the bottom of the tank in their search for food. They don’t really like to show themselves, but in the moments they do, they’ll probably brighten up your tank.

    Mandarin Fish are quite peaceful, ignore other fish, and they’ll just hide whenever they feel threatened. Males might fight, so make sure you keep the male-to-female ratio to 1:1.

    Mandarin Fish Tank Mates

    The Mandarin Fish don’t like to compete for food or territory, so they need to be kept in the same tank with others that share the same behavior.

    So, pair them with Coral Beautys, Firefish, Green Chromis, Pajama Cardinals, Clown Fish, even Royal Grammans. Avoid any live anemones as they could consume the Mandarin Fish.

    Angelfish (Pterophyllum)

    Angelfish (Pterophyllum scalare) in aquarium
    Angelfish (Pterophyllum scalare)

    Originating from the Amazon Basin, the angelfish (genus: Pterophyllum)  are small ambush predators that can prey on small fish or invertebrates while looking cute and innocent. Would it be a great idea to fill a 50-gallon tank with these “angels”? Let’s see!

    • Care Level: Easy
    • Temperament: Semi-aggressive
    • Diet: Omnivore
    • Water temperature: 24 °C to 28 °C (75 °F to 82 °F)
    • Size: 6 Inches
    • Family: Cichlidae
    • Lifespan: 10 years

    Angelfish Appearance

    Their small bodies can grow up to 6 inches, while their fins can reach as high as 8 inches. That is something. They all look like some highly-active arrowheads, with some triangular snouts and a wide fan-shaped caudal fin.

    Angelfish are usually gold or silver, but you could also find them black or some even marbled. Depending on the species, some angelfish have black spots; others present irregular bands of colors on their body.

    Angelfish Temperament

    The Angelfish are quite an enigma. They are cute and little but could also become aggressive. They usually dwell in small hierarchies and fight to maintain their hierarchical positions. The locking of their lips is the sign they are starting to fight.

    They could dwell in small schools, although they’re no social animals. Sometimes they could hide in the middle areas of the tank between the plants; other times, they might be showy. They’re quite entertaining as a whole.

    Angelfish Tank Mates

    These little guys are quite pretentious when it comes to tank mates. One choice would be to keep them with other Cichlids, like the Dwarf Child, or Bolivian Ram, which are harder to be bullied. The Angelfish are not that angelic after all.

    Other good mates could be the Mollies or Dwarf Gouramis. Do not choose any invertebrates as they might be preyed on by the Angelfish.

    Conclusion – The Best Fish For A 55-Gallon Tank

    As you can see, there are a TON of different fish you could add to your tank. Given that there are so many different options, it may be difficult to decide which fish to add to your community. However, 10 of the best fish for a 55-gallon tank are mentioned right here. What would you choose? I hope this guide has helped you with your decision!


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