Most fish are carnivorous. Only a few species, such as the saupe, feed on algae. Fish do not have a well-defined diet. They eat the most abundant organisms in the environment where they live. Generally the prey changes during growth.
Thus, the larval fish feeds exclusively on plankton. The juvenile fish looks for mollusks, which are a bit bigger. The adult fish eats preferably crustaceans, mollusks, fish eggs and larvae or adult fish.
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Which fish is a herbivore?
The herbivore is at the opposite end of the food chain from the carnivores. Although herbivores can sometimes be seen eating live food, the proper diet of a herbivore consists of plants, algae and fruits.
They do not have a true stomach; instead, they have a specialized intestine capable of breaking down plant matter. Their teeth are flat, which allows them to grind food before swallowing it. Lacking a stomach to hold large quantities of food, herbivores must eat frequently – at least several times a day.
Since herbivores require frequent feeding of vegetables and fruits, they are often not the best choice for a community aquarium. The following is a non-exhaustive list of herbivorous fish that exist:
Blue Parrotfish (Scarus coeruleus)
Belonging to the Scaridae family, this herbivorous fish is distributed in tropical and subtropical areas in the western Atlantic Ocean and the Caribbean Sea, where it lives in shallow waters with sandy bottoms and coral reefs. It can measure from 30 to 80 cm and it is characterized for its intense blue color and for its “beak” located at the level of its mouth formed by jaws as well as a hump, present in the males and the females, on the head.
Their beak allows them to feed on the algae available in the coral reefs, which makes them participate in the control of their populations and, thus, prevent them from covering completely the corals.
In addition, they have pharyngeal teeth, that is to say that in the throat they have teeth that allow them to gnaw the coral and the rocks while allowing them to triturate them forming, in this way, sand that will be expelled by the fish. This is how blue parrotfish play a very important role in the formation of sandbanks and small islands.
Brazilian Saupe (Kyphosus sectatrix)
Belonging to the Kyphosida family, the Brazilian Saupe inhabits tropical and subtropical coastal waters all around the world. It can be observed in rough areas and shallow places where there are algae and rocky and sandy substrates. It is a fish that measures between 50 and 70 cm and the shape of its body gives us the impression that it has a long snout.
Its color varies between greenish tones to gray at the level of the belly, but individuals can curiously be of yellow colors with spots. It is a schooling fish and it is common to see them alongside other species of fish. They feed mainly on brown algae, but if the situation requires it, they can also consume mollusks and aquatic mammal waste, such as those of dolphins.
Saupe (Sarpa salpa)
The saupe is a herbivorous fish of the family Sparidae present in the Mediterranean, the North Atlantic Ocean, the Bay of Biscay, the Mozambique Channel, the Canary Islands, Madeira and the Azores. In general they live at a depth of about 15 to 20 meters.
It has an oval and compressed body of about 50 cm long, it is of grayish color with characteristic orange bangs located on the sides of the body and it is possible to observe on its back a single dorsal fin. It is a gregarious species that always swims in company and, although the adults are herbivorous, the young are omnivorous.
They always swim in groups and they consume several types of algae, most of them belonging to toxic exotic species, so that its consumption can cause health problems in humans. As one of the few species of herbivorous fish present in the Mediterranean, the saupe plays an important role in safeguarding the ecosystem.
Blue surgeon (Paracanthurus hepatus)
Also known as the pallet surgeon, this fish belongs to the family Acanthuridae and is found in many seas around the world, such as Australia, Asia and Africa. It lives in areas with coral reefs at depths of more than 30 meters, using some corals to hide from some predators.
It is a species that measures about 30 cm in length, it is of brilliant blue color on the whole body, two black bangs on the sides and with pectoral and caudal fins on which we can see yellow details. For their colors and shape, they are frequently captured by aquarists.
The young usually swim in groups and they feed exclusively on plankton. Adults are not strictly herbivorous, but they base the majority of their diet on the consumption of macro-algae.
Red-banded parrotfish or rainbow parrotfish (Sparisoma aurofrenatum)
This fish of the Scaridae family is endemic to the western Atlantic Ocean where it lives from Bermuda to Brazil, including the whole Caribbean area. It can live up to a depth of 70 meters, but in general it prefers coral areas where there are algae and marine plants that are part of its diet.
It is about 30 cm long and has a reddish color on the whole body, its fins are red and it is recognizable for the black spot that is behind the operculum, although some individuals may not have it. The young ones, on the other hand, are of brown color and their belly is red.
In general, it moves in small groups and at the time of reproduction it moves in the marine funds where there are zones of grazing and where it reproduces. It is a protogynous hermaphrodite species, that is to say, it has both sexes until the reproductive period, when it turns into a male. Discover more hermaphroditic animal species!
Oceanic barbel fish (Acanthurus bahianus)
The oceanic barbier surgeonfish belongs to the family Acanthuridae and it lives in tropical areas of the western Atlantic Ocean where it lives in coral reef areas with sandy bottoms and in the presence of algal meadows, being one of the most common herbivorous species in the places where it lives.
It is a fish with an oval shape and it can reach more than 30 cm of length. It is of a brown/purple color with more yellow fins, a slightly elongated beak and a small mouth.
They form small territorial groups, in which are found other species, such as the bayolle surgeon (Acanthurus coeruleus) with which they patrol their territory where they feed at depths of up to 40 meters.
Grass carp (Ctenopharyngodon idellus)
Also called grass carp, it is a fish of the Cyprinidae family native to Asia and also present in Siberia and China where it inhabits rivers with slow water and abundant aquatic vegetation, which can be found up to 30 meters deep.
It is a species very tolerant to the salinity of the water as well as to the deficiency of oxygen. They can measure more than a meter and their body is of brown/greenish color.
It is a species that was introduced in the United States and Europe to control the growth of certain aquatic plants. In addition, it is one of the most used fish in aquaculture, because it is extremely fast growing. The grass carp feeds mainly on algae and Atlantic plants, but it can complete its diet by eating detritus or insects.
Silver carp (Hypophthalmichthys molitrix)
This species of fish belongs to the Cyprinidae family and is native to East Asia. It is possible to see it in China and Siberia, in addition to some other countries where it has been introduced. It lives in temperate and subtropical zones, in rivers and lakes with slow water where it is common to see them near the surface.
The silver carp is about a meter long and has a greenish/silver color, from which it gets its name. Unlike other carp species, this fish has eyes located at the level of the belly.
Its introduction to other countries is due to the fact that they were used to control populations of filamentous algae and certain species of aquatic plants, but as is the case with the Koi carp, its populations have caused many ecological problems in some areas, as they consume all types of plants, not only those they were intended to control, thus becoming an invasive species.
Johannii (Melanochromis johanni)
This fish is endemic to Lake Malaewi in East Africa where it is found in rocky areas over 15 meters deep. Their body is elongated and it measures about 10 cm long, the female being smaller and of yellow color or with more obscure bands on the sides. The male, on the other hand, has a body of blue color with white or lighter bands on the sides.
The Johannii is a quiet and gregarious species, although it is territorial with males of the same species or genus, because they have the same colors and can confuse them with those of its species. In general, they consume algae stuck to the rocks and plankton and that is why it is common to see them in rocky bottoms.
What are the other types of fish?
Not all fish require the same diet. Like other organisms, a fish is designed with a mouth, teeth and digestive tract for certain types of food.
It is important to keep in mind that any living creature will eat almost anything if it is hungry enough. In other words, don’t make general assumptions about a fish’s dietary needs based on observation alone.
These are meat-eating fish, and usually require live food. They have large mouths with sharp teeth that allow them to grab their prey and tear off large chunks of flesh, which are swallowed whole rather than ground or chewed first.
Carnivores have a short intestinal tract and a relatively large stomach designed to hold a whole fish. Their digestive system does not have the capacity to digest plant material.
Therefore, although they can eat plants, they cannot get nutrients from them like other types of fish. Because they will hunt and eat other fish in the aquarium, carnivores are not suitable for a community aquarium.
An omnivorous fish will eat a variety of meat and vegetables. Although omnivores can and will eat plant material, they cannot digest certain types of grains and plants. Their teeth and digestive tract have some of the traits of both carnivores and herbivores.
Omnivores are the easiest fish to feed because they eat flakey foods as well as live foods and everything else. For this reason, omnivores are an excellent choice for a community tank.
As you can see, it’s important to feed your fish properly, as their bodies are designed for certain types of food. If you are not sure what type of food your fish needs, use the food type chart.