Freshwater fish aquariums are a beautiful addition to any home.
There are many species of fish to choose from that all have different colors and characteristics.
Although most freshwater fish can live within the same water parameters as each other; this doesn’t mean they can all be housed with each other. Freshwater aquarium fish come in a wide range of sizes and personalities. These differences can cause fights since some fish are territorial.
Before adding more fish to your tank, it is important to do your research on what species of freshwater fish can go together to create a peaceful community tank.
Fish Compatibility: What is it?
While some may think that all aquarium fish can be housed together, this is not the case.
Just because they may all live in freshwater and have similar environments does not mean they all have the same temperament or social behavior.
Fish compatibility is overall the ability for different species of fish to peacefully coexist. The key word here is ‘peacefully’.
While many different species of schooling fish are peaceful, others are extremely territorial and should never be placed with small community fish.
There are also a few species of freshwater fish that are significantly larger than the others and can do harm quite quickly if placed with small fish.
It is crucial to do research on different species before putting them in a tank together.
Common Freshwater Community Fish
Common freshwater community fish, or schooling fish, tend to be smaller peaceful fish.
Some of the following are more popular community fish that you are more likely to see in a home aquarium.
Some popular choices for community fish are:
- Harlequin Rasbora: This moderately active unique looking fish goes well with shyer breeds. They are smaller and grow up to 2 inches in length. They do like to be kept in groups of about 8. The harlequin rasbora is named after their joker costume appearance.
- Guppies: Guppies are one of the most popular beginner community fish. They have a vast range of colors that always catch the eye. Guppies also are small in size and can grow up to 2 inches. They are perfect for a smaller tank, but they can spawn rather quickly. If you are looking for colors, it is recommended to only get males to prevent overcrowding from spawning.
- Neon Tetra: These little fish only grow about 1-1.5 inches in size. They are a great option if you have a smaller tank or are looking to add a bit of color to your tank. With their bright colors and neon stripes on their body, they have a fantastic visual appeal!
- Platy Fish: Platies are peaceful fish that grow up about 2-3 inches. There are many different breeds of platyfish, all beautiful, and a great addition to a community tank.
- Otocinclus: These bottom dwellers like to have a group of about six. They are peaceful and small at about 2 inches, they would do well in a community tank. They are also beneficial to tanks because of their cleaning abilities. They love to eat algae!
- Mollies: Mollies are on a larger scale for popular community fish, growing up to 3-5 inches in length. They come in a variety of different colors and patterns and make a beautiful addition to a community tank.
- Corydoras Catfish: These fish are highly compatible with other species since they are bottom-dwellers, which makes them a great addition to a community tank. They can be aggressive when on their own, so they must always be in a group of their own species of about 6 to 8. They are useful for cleaning tanks.
- Angelfish. Angelfish are a beautiful addition to any freshwater tank. They come in an arrangement of colors and are overall peaceful. However, they should not be kept with fin-nippers.
A fun fact about angelfish is that they tend to love to swim vertically instead of horizontally.
With that being said, they do make vertically taller tanks.
They also need enough room to swim, so ensuring that the tank is not overcrowded is essential.
Aggressive Freshwater Fish
Some of the most popular freshwater aquarium fish are some of the most aggressive and territorial.
Thorough research of any aggressive fish is necessary to avoid injury or death to your other fish.
However with proper care, and observation, you can manage their aggression.
The following are examples of aggressive fish that should not be put in a community tank or some that can be with proper planning.
- Tiger Barb: These fish are known for bullying peaceful fish and nipping at longing at larger flowy fins. Tiger barbs prefer to stay in groups of at least six, as they are shoaling fish. In some cases being in a group helps simmer down their aggressive behavior. Therefore proper planning is needed for them to be part of a community tank.
- Bucktooth Tetra: This is an example of a fish that should only be amongst its own species, even away from other tetras. They can grow up to 5 inches and do well in groups of at least 12. Anything less than 12 can lead to fighting over dominance.
- Afer Knife: This aggressive fish can grow up to 20 to 30 inches in length. The afer knife doesn’t do well with others, even its own kind as it is highly predatorial. Because of this, they prefer live food, and you can provide them with feeder fish. This however is why they should not be a part of a community tank.
- Dwarf Pea Puffer: Even though this fish only grows up to about 1.5 inches, they are considered quite aggressive and are known for fighting with other fish. Dwarf pea puffers should not be in a community tank but only with their own kind. However, even then there needs to be plenty of extra room in your tank to avoid fights over territory.
- Convict Cichlid: One of the most popular cichlid species, they love to stay active and hide. They have silver and black stripes all over making them look like prisoner costumes. They can go with other cichlids but again, can get very territorial. Never put these with smaller species and they can end up being eaten. Although they can be aggressive, they can be managed within a community tank. By providing enough to roam by having a larger tank and lots of different places to hide they can feel safer and stay more docile.
- Oscars: This is a very popular fish in freshwater aquariums. These are aggressive fish as they tend to be bullies, and can attack or eat other fish that are vulnerable. They can be part of a community tank, just as long as it is with other slightly aggressive fish that can hold their own. These guys can grow up to 10 to 12 inches. With that being said, a large tank would be needed for an oscar alone. Add even more space for other fish if added. With that being said, they are better off alone.
- Jack Dempsey Fish: These are very territorial fish that can grow up to 15 inches, and need to be given plenty of hiding spots that they can claim as theirs. With their huge size, they would need a large tank and would be better off as the only fish in the tank.