Loneliness is a human emotion and whether or not a fish can feel this emotion is heavily under debate. With that being said, different species of fish are meant to live in a school of fish, and others are not.
The general consensus is that fish do not get lonely. Fish do not display any human-like emotions and therefore can’t feel lonely. However, certain fish species will be visibly stressed when left alone for too long. Other species prefer to be solitary and are aggressive when placed with others.
Again, the ranges of emotions we face as humans are not portrayed in fish. Whether a fish tends to get stressed when alone depends heavily on the species of fish that they are. If you are looking for a single fish, or a group of fish, read on to learn more about their social habits.
Solitary Fish
While some fish love to be in groups of ‘friends,’ others have a predatory instinct and are territorial and should never be placed in an aquarium with others. If you plan to house one of these fish in your aquarium, ensure they are separated from the others.
Piranhas
We’ve all seen piranhas in movies that portray them as manic flesh-eating fish, and the movies portray them correctly! Piranhas should never, ever be placed in an aquarium with other fish. They will be eaten almost immediately.
Only keep them with other piranhas.
Keeping the lid on any aquarium with piranhas is also crucial because they are known to jump out of the tank out of anger.
With that being said, owning piranhas may not be legal in your area, particularly in southern America, so make sure you do your research before purchasing one.
The Betta Fish
The Betta Fish is a species of fish that is unique in its demands and needs. They are commonly found in small plastic containers in your local pet shop. Despite what is advertised, these fish are specific to their needs. Betta fish are also commonly called Siamese Fighting Fish.
In order for a betta to thrive, you must provide them with perfect water conditions, spacious tanks (again, not what is advertised), and water plants. If your Betta appears stressed, one of these factors is not up to standards.

Despite the “lonely” appearance, betta fish are pretty content living alone in an aquarium, but they do need enough space. The small fish bowls are not enough for a betta and do well in at least a 5-gallon tank. This gives them room to explore.
Betta fish are highly aggressive and territorial in the wild and prefer to live alone in captivity. This is why you should never house two males in the same aquarium. While they are beautiful little fish, one will end up hurt.
Betta fish like to fight, (it’s like a hobby for them) if they are in an aquarium with other fish, especially those that are sociable. Again, never place any other fish with a betta. While this holds true for males, it is possible for females to be housed together. However, at the pet store, you are usually greeted by males.
Oscars
Oscars are on the larger end of the spectrum when it comes to fish for your home aquarium.
Oscars can adapt and survive on their own, even if they can sometimes be found in pairs or groups in the wild.
Oscars are predatory fish, so be careful which species you put in with them. They can eat or injure other fish in the aquarium if the other fish are not as powerful or big as the Oscar fish. This is why the Oscars should be kept alone.
Since they are so large, they tend to take up all of the room in the tank anyways. It is best to have at least a 75-gallon tank for one oscar with limited decorations.
Social Fish
While fish do not get lonely, there are smaller freshwater fish that love to live in a community of other fish. If they are not placed together with others, they will survive, but not as long as they normally would.
Guppies
Guppies are one of the smallest freshwater aquarium fish. They are gorgeous and have a pleasant demeanor, meaning they not only get along with their own species but other sociable species as well.
These are not schooling fish, but they enjoy the company of other guppies. If you do not have at least a pair of them, they will not live too long. However, the more, the merrier. One thing to keep in mind about guppies is that they spawn rather quickly.
With that being said, if you have both sexes in your aquarium, you will more than likely end up with fry and your aquarium will be overrun. If you want to avoid this problem, get a few males (more colorful) or females, but not both.

Swordtails
Swordtails are a bit bigger than guppies but are just as sociable. They also have a charming demeanor and can be housed with multiple different species.
If you do not want to breed the swordtail, be sure only to purchase females as they spawn quickly as well. Swordtails come in various bright colors and can make your home aquarium come alive.
Platies and Mollies
Both platies and mollies can typically live on their own, but they are very social creatures and prefer to live in groups. If you have a large community tank, you can add two of both and watch them chase each other and play in the aquarium.
You will again want to watch the ratio of males to females to ensure that you don’t end up with an overpopulated tank.
Discus Fish and Angelfish
Discus and angelfish are on the larger end of the spectrum when it comes to freshwater community fish. They are all pleasant, but with their size comes the need for a bigger tank.
Discus fish also prefer to be around their own kind and are best in groups of around 4. If you have other species of fish, ensure there is enough room for all of them.
The term ‘discus fish’ also includes species such as gouramis and the Bolivian Ram Cichlid (other cichlids are aggressive).
Freshwater Community Fish
On top of the short list above, there are a few other species that do well amongst a community of fish and are well-sociable.
- Minnows
- Danios
- Catfish
- Plecos
- Tetras
- Rasboras
- Pencilfish
- Siamese Algae Eater
- Rainbow Fish
Somewhere in the Middle Fish
Again, fish do not get lonely, but as the list suggests above, some species are happier than others when they are a part of a community. There are also others who are better off completely solitary. With that being said, there are a few species of fish that are somewhere in the middle.
Goldfish
Goldfish are usually advertised as fish that do well in a small fish bowl as decoration in the living room. However, this is not the case. Goldfish grow to the size of their environment and with that being said, can grow quite large.
Keeping this in mind, a goldfish that has a large enough tank, and proper parameters will be quite ‘happy’ with the environment and do not need any further company for socialization.
However, they also do fine with other fish of their kind. They can become territorial in the wild and you must make sure there is enough room for all of them.