How to Choose Compatible Fish for Your Community Aquarium

Amar Salvi has been a nature aquarium enthusiast for over 35 years and owns his own Nature Aquarium Gallery in Navi Mumbai, India.

Fish Compatibility Is the Key in Any Aquarium

Before getting tempted to add whichever fish catches your fancy into your community tank—spare a thought for that word 'community'!

The fish have to be compatible with each other (read: co-exist peacefully). It is also important to check whether they have the same needs. For example, some fish, such as goldfish, need cold water, while most others are tropical fish, needing warm water.

Let's understand this a little better. There are literally thousands of species of freshwater fish out there—only some of these are suitable for your aquarium, and others are best kept alone (like in a single fish species tank) or in the company of similar fish (as in cichlids). Out of the fish that can live in your aquarium, some are especially suited for community tanks due to their harmonious natures.

The 'Community' in My Community Tank

I approached the tank shown above with a view to keep discus fish as the primary showpiece. The rest of the fish were chosen for their compatibility with discuses. Given that I use my planted tank as a 'grow-out' tank for the baby discuses once they are weaned away from their parents, the choice of super-compatible species was all the more critical.

I planned my tank to ensure that I have fish occupying all the levels of the aquarium, from surface feeders who will take the first bites of the food, to mid-level feeders and finally bottom-feeders who will take care of the food settling down.

  • Surface Feeders: In my tank, I have zebra danios, line danios, and one Endler's guppy. With their mouths turned upwards, these fish are adept at catching insects or food that falls in the water.
  • Mid-Level Feeders: I have a shoal of rummy-nose tetras, harlequin rasboras, and the discus babies that take up this space. Neons, cardinals, black neons, etc. make an excellent addition at this level.
  • Bottom Feeders: Here I have some corydoras and a bristle-nosed whiptail catfish. I also have about six otocinclus who are working 24/7 cleaning off the algae from the glass and leaves. I also have a clown loach who makes a guest appearance during feeding time.

All in all a peaceful lot living in co-existence—live and let live.

Keep These Points in Mind When Checking for Compatibility

  • Research before you buy. This is probably the most important thing you can do as a favor to yourself and all the fish concerned. The internet is the best source for this information. Some sites I found useful are AquariumFish.Net and Tropica (if you are into planted aquariums).
  • Don't just go by what the pet store guy has to say about a fish's compatibility. Look it up yourself. Many fish are shoaling fish, best kept in schools of 10 or more. Some others, such as Siamese fighters, are loners, best kept alone. Similarly, arowanas, flowerhorns, Oscars, and other similar fish will not bother a fish of a similar size, but if that fish can fit into their mouths, they won't think twice!
  • Provide enough space for each fish. Overcrowding is another cause of aggression and stress amongst tank mates. Remember that each fish is territorial in varying degrees (cichlids are the most aggressive in protecting territory), and you need to ensure you take care of this aspect. Also take special care of their needs. For example, clown loaches, blackghosts, Synodontis, etc. like to stay in driftwood, while cichlids prefer rocky structures with lots of small caves that they can lay claim to.

Some Suitable Community Fish

FishCompatibilityBest Kept


Compatible & Peaceful

Multiple Pairs


Compatible & Peaceful

Multiple Pairs


Compatible & Peaceful

Multiple Pairs


Compatible & Peaceful

Group of 3-4


Compatible & Peaceful

Group of 4-6

Neon Tetras

Compatible & Peaceful

Shoal of 12 or more

Cardinal Tetras

Compatible & Peaceful

Shoal of 12 or more

Rummy Nose Tetras

Compatible & Peaceful

Shoal of 12 or more

Harlequin Rasboras

Compatible & Peaceful

Shoal of 12 or more


Compatible & Peaceful

Shoal of 6 or more

Zebra Danios

Compatible & Peaceful

Shoal of 6 or more


Compatible & Peaceful

Group of 6 if Juveniles or a Pair if Adults


Compatible & Peaceful

Group of 4-6

Siamese Fighter






Upside Down Catfish



Bristle nosed catfish



Blue Gourami

Compatible & Semi Aggressive

One Male & Two Females

Pearl Gourami

Compatible & Semi Aggressive

One Male & Two Females


Compatible & Peaceful

One Male & Two Females

Clown Loaches

Compatible & Peaceful

Shoal of 6 or more

Black Ghost

Compatible & Peaceful



Compatible & Semi Aggressive

Group of 6 if Juveniles or a Pair if Adults

Questions & Answers

Question: how many fish will my 38 gallon tank hold?

Answer: That's quite a big tank you have. The number of fish or the Bio-load the aquarium can handle is a function of whether you plan to have a lot of smaller fish like Tetras or big ones like Oscars, Arowanas,etc. In case you plan to have smaller ones, this aquarium can easily support 100 + tetras or even more. Big fish tend to eat a lot, poop a lot and generally have a lot of food leftover, so in case of bigger fish, lesser the better. They will also need the space as they grow, so I would say max of 12 Oscars or 1 big Arowana with 3-5 Oscars/Piranha,etc...

Arun Kumar on September 08, 2020:

Hi I am an new aquarist in my tank I am having gold fish, mollie,guppies for additional I planning to add new fishes like Green zebra glo, platy fishes shall put all theses fishes in single tank Pls suggest and help me and also which temperature I have maintain in heater

Darin Murphy on July 07, 2020:

I am a new aquarist and have recently made a outdoor tank. This tank is uncovered and already has a small pleco. I tried a few swordtails but they jumped out within the first day: so sad. I plan on adding at least one more pleco and am looking for a few colorful options that will get along well.

Please Help!!!

SharpMindqq on October 22, 2019:

That's helpful, thank you

Dave Bane on January 28, 2018:

Are neon tetras happy with other kinds of tetras as a community?

JH on April 09, 2017:

is adding serpae tetra to a community tank ok?

Jennay on January 26, 2017:

very very very helpful!! I now know what fish to put in my community tank. Good job

Sudhir Bhandarkar on December 05, 2016:

Very insightful write-up sir. Certainly helped me in planning a community aquarium for my home. Thank you!

Prethish Kumar on August 24, 2016:

Sir, You have a gorgeous tank!! May I know what lights are you using in your tank??

Frank on August 19, 2016:

How big is the tank? I have a 45 gal that I would like angelfish as primary. How many angels would be too many, and how many other fish can I have? Is there some kind of formula/equation?

Darren on July 14, 2016:

Do your bottom feeders compete for algae to eat?

Amar Salvi (author) from India on May 13, 2016:

Thanks for the feedback,Joe

Joe on May 13, 2016:

Thank you for sharing very informative.

Amar Salvi (author) from India on February 07, 2013:

Agree. Have learnt that the hard way.

Rich from New Jersey on February 07, 2013:

neons.......can't go wrong with neons, you can go wrong with upside-down catfish that get real big and eat the neons.

mits on January 22, 2013:

Very Useful article... very well written... thanks for this.

Amar Salvi (author) from India on January 18, 2012:

@myawn ...thank you!

myawn from Florida on January 18, 2012:

nice helpful hub thank you for the list of community fish.A good guide for setting up a tank. Thanks!


The biological clock of most fish species is regulated by the light and they will therefore do best in an aquarium where the onset of dusk and dawn takes place at predictable hours. Tropical fish species are used to roughly 12 hours of light per day, year round. Fish species living closer to the poles are used to long summer days and short winter days. The easiest way of providing your fish with a stable rhythm of light and darkness is to connect the aquarium lights to a timer.

Fluorescent lights are a better choice than incandescent lights since incandescent lights emit a lot of heat. This is not only a problem for your fish it is a problem for your electricity bill as well since they consume much more electricity than fluorescent lights.

Freshwater Fish Compatibility Chart

Images courtesy of PetcoBlogger

Freshwater aquariums are really fun to keep when all the tank mates get along happily and are thriving!

Keeping a freshwater fish aquarium is one of the most rewarding experiences. There are many aquatic animals to choose from that will add color and interest to your community tank.

Beautiful Betta and rainbowfish, hardy goldfish, and pretty live-bearing fish like guppies, mollies, swordfish and platies are some of the best known. But to add even more intrigue, there are also exotic looking eels and sharks, African dwarf frogs, snails, and more. It's fun to watch your fish, frogs, snails, or any other critters cruising around the tank. Its also exciting to see their personalities unfold. To the delight of many aquarists, some of these fellows will even come to know their keepers!

How cool is that. your pets gets excited when you approach the tank! However, compatibility between the inhabitants is very important for a happy, healthy, friendly freshwater community. Keep aquarium inhabitants that are good neighbors and everybody will thrive. When tank mates are peaceful and compatible with each other, their best colors come out and it's fun watch them grow.

Keeping tank mates that are incompatible, however, can lead to all kinds of problems. When aquarium inhabitants don't get along, somebody ends up getting picked on. Incompatible tank companions can manifest itself in other ways too. A common sense problem is big fish that want to snack on smaller fish and other critters. Other challenges are inhabitants competing for food, fighting to dominate a position in the tank, or quarrelling over a shelter. All of these situations cause stress which can result in disease, injury, and often times. loss.

Freshwater Fish Compatibility Chart

Friend or foe? Freshwater fish compatibility for a happy tank!

To maintain a happy, healthy, friendly community tank, it's important to ensure compatibility between the inhabitants. The freshwater fish compatibility chart below will give a good overview of the common types of fish that can usually be kept happily together. For first timers, or those who are new to the hobby and are setting up a community tank, this guide can help you make good fish choices. It will help you select fish that can live together in harmony, giving you a happy, healthy, friendly community.

Characteristics of Fish Types Chart

Always pay attention to your fish to monitor any aggression!

Freshwater fish fall into several different groupings, with each fish type having different habitat needs, characteristics, and behaviors. The freshwater compatibility chart above is a great start, but there are several additional factors that need to be considered to help determine whether each species is compatible or not. These include size, temperament and gender diet, activity level, and the areas of the tank they will inhabit and aquarium water parameters like temperature and pH.

The chart below gives an overview of the characteristics of the different types of fish that are most commonly available. However, these fish as well as any others, are not always predictable. An individual fish may not behave in the way its group is characterized.

You may obtain a fish that is "supposed" to be peaceful and friendly, and then it becomes a jerk! On the other hand, you may get a fish that is supposed to be a dominant, solitary, or aggressive species, only to find it hanging out and buddying up with its tank mates. So you need to pay attention to your fish, no matter what their behavior is supposed to be.

Even within the groups shown below, temperaments and behaviors vary with each individual species. After selecting the groups of fish you are interested in, find them here: Aquarium Tropical Fish. Then select your group and read about the individual species within that group

Author: Clarice Brough, CFS

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Best Aquarium Tips

Having a new aquarium means having to deal with the type of fish species you can keep on your aquarium, the size, type, and placement of your aquarium in your home or office, and whether you’ll need to use saltwater or freshwater, plastic or live plants, and the types of heaters, filters, food, and lights. Usually, when a new aquarium owner makes a decision on the type of fish to place in the aquarium, it is based on the appliance and color, and this is a major concern that many are struggling with. The correct way in setting up a new aquarium in to research what type of fish will best be put in your aquarium by knowing the maximum length or size of the fish, its compatibility with other fish, if it will tend to eat smaller fish, and if it nips the fins of other fish.

It is best to tailor the type of species at you choose to the type, size, and location of your aquarium, along with your heating and filtering choices. There are three thousand of fish species available and there are seven categories to help you know them including catfish, characiforms, cichlids, cypriniforms, cyprinodonts, labyrinth, and rainbow fish. Catfish have over 2,000 species with their own unique characteristics, with armor-like skin or plating, used as aquarium scavengers, and some are specialized feeders, nocturnal, and need to live in live groups. Characiforms are usually wild caught including piranhas which are best suited to experts, and smaller species are used in community aquariums.

Cichlids are aggressive so they are suited for live aquariums, they have bright colors, diverse habitat, and can live in a community aquarium given the right conditions. One example of coldwater fish under the cyrpiniform category are goldfish, and cypriniforms are popular as aquarium pets because of their hardiness, willingness to breed, and easy of care. If you are a beginner, avoid taking care of cyprinodonts because it will be difficult for you to handle tooth carps consisting of egg layers as well as swordtails, mollies, guppies, and platys. Labyrinth fish are hardy, small, and peaceful fish which are suited for community aquariums. View this website to know more about pets.

As a beginner, you need to start researching on the individual fish and requirements, building a nice aquarium according to the needs of your fish. You can visit our homepage or website for more details about aquarium and fish care. Having aquarium pets from Aquacadabra can be exciting not just for you but most especially for your children. It is best to set up a fish aquarium now to enjoy reaping the benefits as soon as possible!

What’s the most popular pet in America? Most people would say dogs or cats, but based on sheer number, the answer is freshwater aquarium fish. While fish can’t cuddle like warm-blooded pets, they offer their owners constant beauty and a calming influence. Fishkeeping is also a wonderful family endeavor.

For ease of maintenance, bettas can’t be beat. Also known as Siamese fighting fish, bettas require separation from most other species, which means these brilliantly colored swimmers do well in small fish bowls. While keeping male bettas separate is imperative, some female bettas can live in tanks with other fish. Bettas are a cold-water species.

Another cold-water fish, goldfish belong to the carp family. Because they enjoy cool water temperatures, keep goldfish in a separate tank from warm water fish. Avoid keeping goldfish in a bowl, as they can grow quite long and need sufficient swimming room. Because they do grow so large, don’t overcrowd your goldfish tank. Well-kept goldfish can live for many years.

3. Angelfish

Large, lovely and graceful, angelfish appear in various color patterns. Because of their size when full-grown, angelfish require at least a 55-gallon tank. Angelfish do well with other fish species (although they may eat very small fish) but can fight with each other. Provide plenty of plants in the aquarium, as angelfish like to hide beneath them.

Catfish aren’t the most spectacular fish in a tank, but they serve an important purpose. These low-maintenance, bottom-dwelling fish consume algae growing in the tank, so they aid in keeping the tank clean. Choose among various catfish species and colors. Most types of catfish are compatible with the fish commonly kept in community tanks.

These easy-care aquarium fish appear in a variety of colors. There is one drawback to guppies: They breed constantly, so if you have male and females together, the offspring can soon overwhelm a tank. For best results, choose all males or all females. The former sport longer tails and brighter colors.

These small, hardy fish do best in tanks with heavy filtration. Unlike many tropical fish breeds, mollies bear live young rather than lay eggs. If you want to raise mollies, a ratio of one male per three to four females works best. Too many male mollies stress out the females with constant breeding. Mollies tend to nip the fins of other species, so you may want to keep them in a separate aquarium. Keeping a few mollies in a community tank can work out well.

7. Neon Tetras

These small, translucent blue and red fish hail from the Amazon jungles. Because they aren’t aggressive, they are a welcome and colorful addition to any freshwater tank. Keep neon tetras in a school of at least six fish, and preferably more. You’ll find them swimming in the middle of your tank.

Platies are ideal for those getting started in tropical fishkeeping. They are available in dozens of shades, and their harmonious natures mean they are good community fish. If you only have room for a smaller tank, around 10 gallons, little platies make a good choice. These active fish tend to swim mid-tank.

9. Swordtails

The larger the tank, the larger you can expect swordtails to grow. The name comes from their sword-like tails, and these fish most often sport a red body with a black tail. Swordtails make good fish for the beginning hobbyist, as they don’t require any special care, although males may fight with each other. It’s best to keep swordtails in a larger tank, or at least one larger than 10 gallons.

10. Zebra Danios

Named for their striped bodies, zebra danios are tough fish. They can thrive in a variety of water temperatures, even into the low 60s. Unlike many species, zebra danios mate for life. These active fish are perhaps the easiest of the egg-laying species, if you want to breed them. Zebra danios swim all over the tank, and make good community fish due to their peaceful nature.


Setting up a proper freshwater fish community is the first step every beginner should take. Once you figure out all the do’s and don’ts of caring for these freshwater breeds, you will be ready to convert to more demanding ones.

However, it is not as if the difficulty level will determine the awesomeness of your aquarium. Freshwater community fish can be just as fascinating as other species with different temperament or more complex needs.

A great way to go about it is to pick one breed and then slowly add more as you figure their needs out. You will slowly end up with a rich community of colorful fish that you will be proud of.

Watch the video: Selecting Saltwater fish (July 2021).