Fish can be classified into three categories based on their diet.
They’re either herbivores, carnivores, or omnivores.
Most fish are omnivores that eat plant matter and meat to get the required nutrition.
Here’s are all the main omnivorous fish.
Omnivorous Fish
Angelfish
Angelfish are tropical warm water fish from the Cichlid family, native to South America.
These fish require warm, slightly acidic water with lots of plants and sunlight.
In general, angelfish are good community fish.
Avoid keeping them with fin-nipping species or small fish that will fit in their mouth.
Angelfish are omnivores.
They primarily feed on plant matter, small fish, insects, larvae, fish eggs, and other tiny crustaceans in their natural environment.
As these fish grow older, they may become aggressive, mainly if housed in an overcrowded aquarium.
Arowana
Arowanas are freshwater bony fish belonging to the family Osteoglossinae.
These fish are also known as bony tongues. They’re pretty aggressive and move around very swiftly.
Arowanas eat both meat and plant matter.
They can eat anything from pellets, flakes, bugs, and live or frozen food to vegetables and lots more.
However, these fish have a preference for a meat-based diet.
Ensure that they eat a healthy diet. Arowanas are susceptible to contracting infections from food, especially if it isn’t hygienic.
Some compatible fish species that you can keep with arowanas are clown knife fish, pacu, oscars, jaguar cichlids, green terrors, gar, and siamese tigerfish.
Cherry Barbs
Cherry barbs are freshwater fish native to Sri Lanka.
They’re found in two river basins: the Kelani River basin and the Nilwala River basin.
Male cherry barbs are usually smaller than their female counterparts.
Cherry barbs are omnivores that eat algae, plants, crustaceans, small insects, and detritus in the wild.
So a well-balanced diet is essential for them to maintain their overall health.
Cherry barbs are small schooling fish that do well when kept in community aquariums.
These fish exhibit fascinating schooling behavior and spend most of their time at the middle level of the tank.
These fish tend to be shy when placed in a large tank with larger, aggressive fish.
So keep them in a small group and choose their tankmates carefully.
Corydoras Catfish
Cory catfish are native to South America, from the highlands of Peru to the Atlantic coast of Brazil.
These fish live in small, slow-moving, clear streams with sand and gravel beds.
They’re also known as cory cats and are commonly found in most freshwater aquariums.
Cory catfish are bottom-dwelling omnivores that eat algae pellets, shrimp pellets, fish flakes, worms, and anything else that fits in their mouth.
Cory cats are amiable and thrive best when kept in groups of two or more.
They get along well with most tankmates in a community tank but avoid keeping them with aggressive fish.
Discus
Discus are freshwater fish found in the floodplain lakes and flooded forests of the Amazon River basin and its tributaries, such as the Rio Negro.
A discus is known as the “king of aquariums” because of its gorgeous and royal colors.
However, this fish needs a well-balanced diet and specific water parameters to stay healthy and thrive.
Discus are omnivores that eat plants and forage at the bottom in search of small crustaceans and invertebrates.
So you can feed them algae wafers, flakes, pellets, and granules in captivity.
Discus fish are one of the most adored fish for their beautiful colors and docile nature.
Goldfish
The common goldfish is a freshwater fish that inhabits the waters of East Asia.
Goldfish are colorful fish that are extremely popular in the aquarium hobby.
Goldfish require a lot of swimming space and must be kept in a large tank.
The water movement in the tank must be gentle to replicate the slow-moving waters of their natural habitat.
They eat algae growing on the rocks and logs and decaying plant matter in the wild.
They also eat small fish, tiny crustaceans, aquatic insects, and mosquito larvae.
Goldfish are social fish that enjoy the companionship of other fish.
So you should house goldfish with other fish that are similar in size and temperament.
Guppies
Guppies are native to northeast South America. They also inhabit the waters of Guyana and Brazil.
However, they have been introduced to different environments and are found worldwide.
Guppies are omnivores that feed on algae, plant remains, vegetable matter, tiny crustaceans, diatoms, aquatic insect larvae, etc.
Guppies are small but active fish. They need plenty of room to swim in their tanks.
Therefore, a larger tank is preferable because it provides enough space for all the fish.
Guppies don’t need much maintenance and are docile and easy to handle.
Their best tankmates are their own kind, and they must be kept in groups of at least six or more for them to thrive.
Mollies
Mollies live in fresh streams, coastal brackish water, and marine waters from Mexico through Colombia.
These fish have been interbred, resulting in different color varieties.
Mollies thrive best in environments that mimic their natural habitat.
So add plenty of aquatic plants and lots of places for them to hide inside the aquarium.
Mollies are omnivores and will need a diet of both plant and animal food.
They mostly eat plant-based food but also enjoy live or frozen bloodworms, daphnia, and brine shrimp.
Mollies will thrive in most freshwater aquariums with shrimp, snails, and other fish that are similar in size.
Keeping them with large, aggressive fish can be fatal.
Oscars
Oscars are freshwater fish native to South America.
They inhabit the slow-moving waters with lots of submerged vegetation and debris, allowing them to hide from predators.
Among aquarium fish, oscars grow big.
A fully grown oscar reaches up to 12 inches in captivity. In the wild, they can grow up to 16 inches in length.
Oscars are omnivorous fish.
They feed on plant matter, small fish, insect larvae, live insects, snails, shrimp, crustaceans, fruits, and nuts to get the nutrition for overall growth.
Oscar’s live in relative harmony with one another as long as each fish has adequate space to claim its territory.
You can also keep them with fish of similar size and temperament.
Platies
Platies are a common name for freshwater fish in the genus Xiphophorus.
They’re native to the east coasts of Central America and Southern Mexico.
Platies are popular among tropical fish keepers.
They’re found in several different color variations, including red, yellow, orange, white, and blue.
Platies are omnivorous with a higher preference for plant-based food than meat.
They need a good balance of plant-based food and protein.
They’re a great community fish, very peaceful, and get along with guppies and mollies.
It’s better to keep them with smaller and docile fish species.
Plecos
Plecos or suckermouth catfish are tropical freshwater fish found in tropical northeastern South America.
These fish are mainly native to northeastern Brazil, Guiana, and Trinidad and Tobago.
In plecos, there is gender dimorphism, meaning the males and females are different in appearance.
Generally, male plecos tend to be slightly larger and longer than female plecos.
Plecos can be herbivores, carnivores, and omnivores as well.
However, the bottom-dwelling omnivores will eat just about anything that comes their way, including algae, wood, plants, and small insects.
Plecos are often appropriate companions for other types of freshwater fish in community aquariums.
However, adult plecos can’t get along with others of the same species.
Rainbowfish
Rainbowfish are small freshwater fish belonging to the Melanotaeniidae family.
They live in fresh waters throughout Australia, Madagascar, Indonesia, and New Guinea.
Rainbowfish are schooling fish. It’s best to keep them in schools of at least six or more.
You must raise these fish in a healthy environment with fresh water and live food to eat.
In the wild, they eat food that floats on the water’s surface, including floating vegetation, insects, small crustaceans, zooplankton, and mosquito larvae.
Rainbowfish get along well with their own kind and do best in groups.
To keep different species of rainbowfish together, you must ensure they’re similar in size.
Swordtails
Swordtails are freshwater species native to North and Central America.
They’re attractive and popular species in the aquarium community.
Swordtails are adaptable, easy to care for, and not very demanding. In other words, it’s not a difficult task to take care of them.
They’re omnivores that eat just about anything in the wild.
They’re known to eat bug larvae, detritus, and tiny microorganisms to get the required nutrition.
Swordtails aren’t shoaling fish, but they enjoy the company of their own species.
They’re docile and peaceful and get along with most like-minded species.
Tetras
Tetras are popular fish in the aquarium hobby. They’re native to Africa, South America, and Central America.
However, they mainly inhabit the warm waters of the Amazon river in South America.
Depending on the species, they can be found in various colors such as red, orange, blue, white, yellow, green, silver, black, and other colors.
Most tetras are omnivores.
They feed on plant matter, algae, floating insects, larvae, and tiny invertebrates in the wild and need a balanced and diverse diet.
Tetras are social and do well with other non-aggressive and similar-sized fish.
However, the best tankmates for tetras are other tetra species that can easily thrive in similar conditions.
Zebrafish
Zebrafish are freshwater fish belonging to the Minnow family. They’re native to South Asia.
This fish is often sold under the trade name “Zebra Danio.”
Zebrafish are hardy and can withstand various water temperatures and environmental conditions.
Unlike most fish, they’re loyal to their breeding partner and mate for life.
They’re not picky eaters and will eat almost anything.
The best food items to feed them are lots of worms, insects, crustaceans, and plant matter to imitate their natural diet.
Keep them together in pairs or a large group.
When kept in a group, a pecking order may emerge. But there is no infighting among them.
