By BETH ANN BATES
What is a community tank? It is a fish
tank that houses more than one
species, a community of fish
neighbors, so to speak. Some hobbyists
specialize in a particular species, and
their tank holds only that species. This
makes it easy to consider the needs of
your fish, since fish of the same species
have the same needs for water
parameters, food, and other living
conditions. However, most beginning
hobbyists are interested in so many
different kinds of fish, that it would be
difficult to choose just one species to get.
So creating a community tank is an appealing idea. This allows you to enjoy several
species, even if you have only one fish tank in your home. But beware, this does not
mean that you can throw any and all species in together.
Not all freshwater fish are compatible with each other. To create a successful community
tank you need to hone your matchmaking skills. How do you decide who will get along?
You’ll want to examine the characteristics of your fish, along with other considerations.
The first thing that comes to mind is size. Size is important, both the size of different fish
species and the size of your aquarium. The size of the aquarium you have now (or are
about to buy) will limit the species you should be considering. Community tanks can be
successful in small tanks, but you shouldn’t expect to keep large fish in small tanks.
Many people shy away from big tanks. Beginners can be intimidated by anything over ten
gallons, but they really shouldn’t be. For a nice community tank, I would suggest a 20 or
30-gallon tank. You could certainly have an even larger tank if you like, but anything less
than 10 gallons is too small for this type of set up.
Remember that the fish you see in the pet store are usually babies. Depending upon the
species, they will grow a little or a lot. Research your potential fish choices! The full-
grown size is one of the characteristics that you will consider in relation to your tank and
in relation to other species. The crowded conditions you often see in stores are not ideal.
Don’t aim to imitate that!
If you look closely, most stores have complex systems of pipes that continually circulate
the water in the tanks, providing a constant flow of fresh water. This is what makes the
crowded conditions bearable for the fish. Naturally, your home aquarium won’t have a
system like this. So you should allow lots of free space. This is especially helpful for
community tanks, because it will give the fish room to hide from each other, if they so
desire. Consider the size of the species in relation to each other.
Large fish don’t see guppies as neighbors, but as dinner! Typically tank-mates will be
similar in size to avoid this problem.
The next consideration is usually the water. For fish of different species to live together
comfortably, they need to be comfortable in similar water parameters. The important
ones to look at are temperature, ph, and hardness. Here again, your research will come
in handy.
Many basic books on aquariums will list the common fish in the hobby and their
preferred water conditions. Fish are adaptable to a range of conditions, so it doesn’t
need to be a perfect match. A wonderful book to have in your collection is The Simple
Guide to Freshwater Aquariums by David E. Boruchowitz. This is a great read for
beginners and includes a chapter on suggested schemes for community tanks.
Another consideration you will research is the preferred swimming levels of each
species. Some species like the lower level of the tank and will stay near the gravel. They
are often referred to as bottom-feeders, various species of cat fish such as corydoras are
good examples. Bottom-feeders can be good neighbors—they scavenge for fallen food
on the gravel and thus help improve the water quality of the tank. Many species are mid-
level or upper level swimmers and will not be bothered at all but the fish that prefer the
bottom of the tank. By combining species that prefer various levels, you are helping to
create a harmonious community.
Some hobbyists like to create what’s called a biotope tank. This is a tank that seeks to
duplicate the environment of a particular part of the world. So the fish, plants, water and
rocks, wood or other decorations would be chosen only if they appear naturally in that
place. Possible examples could be the black waters of the Amazon, or one of the rift
lakes in Africa (Lake Tanganykan cichlids for example). Since the elements appear
together in nature, they should theoretically work well together. These can be beautiful
tanks, but most beginners don’t yet feel the need to get that sophisticated. It’s totally up to
you.
If you like live plants in your tank, you will be choosing plants that like the same water
qualities as your fish, and you will choose fish that enjoy plants. Some fish like to eat
certain plants, leaving the leaves looking ragged. Other fish like to stir up the gravel and
dig up plants. So you may want to avoid those combinations. Any well-planned tank will
match the fish to all the other elements: plants, type of filter and/or heater, gravel,
decorations, etc. For a community tank, the only difference is that you now have more
than one species of fish to consider when matching these elements.
Food is another consideration. When looking at compatibility, look at the food needs of
the species. Some fish need an all-vegetable diet, for instance. In a community tank, you
will not be able to prevent one species from eating food intended for another.
Another concern is the nature of a species, particularly any tendency to be aggressive.
Usually those species with a basically peaceful nature are considered good candidates
for a community tank. If you have your heart set on an aggressive breed, you will need to
take steps to give tank-mates safe havens within the environment. For example, if a large
aggressive fish is placed with a smaller, quieter type, you can provide small spaces for
the little fish to hide in. Hobbyists use clay pots or pieces of PVC pipe for this purpose.
Get pieces of pipe that are too small for the big fish to swim into, but big enough for the
little fish to enter. The smaller fish will learn how to avoid the bully by hiding in the places
you’ve provided. This is not a perfect solution, but it may work.
Spawning behaviors are another thing to think about. Some species are not aggressive
to other fish unless they are spawning. Then they go into attack dog mode. If you want
any or all of your species to be encouraged to spawn in your community tank, then you
will need to know what gets them in the mood, so to speak. Some species need caves or
flower pots to make room for baby, others like plants or rocks. Any fry that are born in a
community tank can become food for the neighbors. The above advice about hiding
places applies here too. Live plants can provide good cover for fry and other small fish as
well. Other hobbyists encourage the larger fish to eat the live food that a spawning
provides. They might have a pair of swordtails in a tank with angel fish for this reason.
Schooling behavior is worth consideration too. Some species like to be in schools, with
usually means a minimum of five or six fish. If you are considering a small community
tank, than this may not be a good choice, because it leaves you little space for tank-
mates. To keep a schooling fish as an individual or pair is not advised. They will become
nervous, uncomfortable inhabitants in your tank. With a larger tank, a group of these type
fish can be a beautiful addition. Their natural behavior can also be amusing to watch.
Look in a good local fish store for a tank of clown loaches and I’m sure you will laugh.
They are really fun.
Community tanks are a great choice for beginners and many experienced hobbyists like
them too. The variety of fish in a well-planned community tank can create an interesting
and beautiful slice of nature in your living-room. My first tank was a community tank of
livebearers. It included fancy guppies and platys. I could have added a few small cat fish
of some kind to that tank.
Planning for a community is a fun way to get to know the different species of fish and
which ones are your favorites. Why not create your own fish block party?
First Published June 2007 in The Animal Companion
What is a community tank? It is a fish
tank that houses more than one
species, a community of fish
neighbors, so to speak. Some hobbyists
specialize in a particular species, and
their tank holds only that species. This
makes it easy to consider the needs of
your fish, since fish of the same species
have the same needs for water
parameters, food, and other living
conditions. However, most beginning
hobbyists are interested in so many
different kinds of fish, that it would be
difficult to choose just one species to get.
So creating a community tank is an appealing idea. This allows you to enjoy several
species, even if you have only one fish tank in your home. But beware, this does not
mean that you can throw any and all species in together.
Not all freshwater fish are compatible with each other. To create a successful community
tank you need to hone your matchmaking skills. How do you decide who will get along?
You’ll want to examine the characteristics of your fish, along with other considerations.
The first thing that comes to mind is size. Size is important, both the size of different fish
species and the size of your aquarium. The size of the aquarium you have now (or are
about to buy) will limit the species you should be considering. Community tanks can be
successful in small tanks, but you shouldn’t expect to keep large fish in small tanks.
Many people shy away from big tanks. Beginners can be intimidated by anything over ten
gallons, but they really shouldn’t be. For a nice community tank, I would suggest a 20 or
30-gallon tank. You could certainly have an even larger tank if you like, but anything less
than 10 gallons is too small for this type of set up.
Remember that the fish you see in the pet store are usually babies. Depending upon the
species, they will grow a little or a lot. Research your potential fish choices! The full-
grown size is one of the characteristics that you will consider in relation to your tank and
in relation to other species. The crowded conditions you often see in stores are not ideal.
Don’t aim to imitate that!
If you look closely, most stores have complex systems of pipes that continually circulate
the water in the tanks, providing a constant flow of fresh water. This is what makes the
crowded conditions bearable for the fish. Naturally, your home aquarium won’t have a
system like this. So you should allow lots of free space. This is especially helpful for
community tanks, because it will give the fish room to hide from each other, if they so
desire. Consider the size of the species in relation to each other.
Large fish don’t see guppies as neighbors, but as dinner! Typically tank-mates will be
similar in size to avoid this problem.
The next consideration is usually the water. For fish of different species to live together
comfortably, they need to be comfortable in similar water parameters. The important
ones to look at are temperature, ph, and hardness. Here again, your research will come
in handy.
Many basic books on aquariums will list the common fish in the hobby and their
preferred water conditions. Fish are adaptable to a range of conditions, so it doesn’t
need to be a perfect match. A wonderful book to have in your collection is The Simple
Guide to Freshwater Aquariums by David E. Boruchowitz. This is a great read for
beginners and includes a chapter on suggested schemes for community tanks.
Another consideration you will research is the preferred swimming levels of each
species. Some species like the lower level of the tank and will stay near the gravel. They
are often referred to as bottom-feeders, various species of cat fish such as corydoras are
good examples. Bottom-feeders can be good neighbors—they scavenge for fallen food
on the gravel and thus help improve the water quality of the tank. Many species are mid-
level or upper level swimmers and will not be bothered at all but the fish that prefer the
bottom of the tank. By combining species that prefer various levels, you are helping to
create a harmonious community.
Some hobbyists like to create what’s called a biotope tank. This is a tank that seeks to
duplicate the environment of a particular part of the world. So the fish, plants, water and
rocks, wood or other decorations would be chosen only if they appear naturally in that
place. Possible examples could be the black waters of the Amazon, or one of the rift
lakes in Africa (Lake Tanganykan cichlids for example). Since the elements appear
together in nature, they should theoretically work well together. These can be beautiful
tanks, but most beginners don’t yet feel the need to get that sophisticated. It’s totally up to
you.
If you like live plants in your tank, you will be choosing plants that like the same water
qualities as your fish, and you will choose fish that enjoy plants. Some fish like to eat
certain plants, leaving the leaves looking ragged. Other fish like to stir up the gravel and
dig up plants. So you may want to avoid those combinations. Any well-planned tank will
match the fish to all the other elements: plants, type of filter and/or heater, gravel,
decorations, etc. For a community tank, the only difference is that you now have more
than one species of fish to consider when matching these elements.
Food is another consideration. When looking at compatibility, look at the food needs of
the species. Some fish need an all-vegetable diet, for instance. In a community tank, you
will not be able to prevent one species from eating food intended for another.
Another concern is the nature of a species, particularly any tendency to be aggressive.
Usually those species with a basically peaceful nature are considered good candidates
for a community tank. If you have your heart set on an aggressive breed, you will need to
take steps to give tank-mates safe havens within the environment. For example, if a large
aggressive fish is placed with a smaller, quieter type, you can provide small spaces for
the little fish to hide in. Hobbyists use clay pots or pieces of PVC pipe for this purpose.
Get pieces of pipe that are too small for the big fish to swim into, but big enough for the
little fish to enter. The smaller fish will learn how to avoid the bully by hiding in the places
you’ve provided. This is not a perfect solution, but it may work.
Spawning behaviors are another thing to think about. Some species are not aggressive
to other fish unless they are spawning. Then they go into attack dog mode. If you want
any or all of your species to be encouraged to spawn in your community tank, then you
will need to know what gets them in the mood, so to speak. Some species need caves or
flower pots to make room for baby, others like plants or rocks. Any fry that are born in a
community tank can become food for the neighbors. The above advice about hiding
places applies here too. Live plants can provide good cover for fry and other small fish as
well. Other hobbyists encourage the larger fish to eat the live food that a spawning
provides. They might have a pair of swordtails in a tank with angel fish for this reason.
Schooling behavior is worth consideration too. Some species like to be in schools, with
usually means a minimum of five or six fish. If you are considering a small community
tank, than this may not be a good choice, because it leaves you little space for tank-
mates. To keep a schooling fish as an individual or pair is not advised. They will become
nervous, uncomfortable inhabitants in your tank. With a larger tank, a group of these type
fish can be a beautiful addition. Their natural behavior can also be amusing to watch.
Look in a good local fish store for a tank of clown loaches and I’m sure you will laugh.
They are really fun.
Community tanks are a great choice for beginners and many experienced hobbyists like
them too. The variety of fish in a well-planned community tank can create an interesting
and beautiful slice of nature in your living-room. My first tank was a community tank of
livebearers. It included fancy guppies and platys. I could have added a few small cat fish
of some kind to that tank.
Planning for a community is a fun way to get to know the different species of fish and
which ones are your favorites. Why not create your own fish block party?
First Published June 2007 in The Animal Companion
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