Uaru amphiacanthoides

Aquarium fish: Uaru amphiacanthoides (Uaru amphiacanthoides)
Size: 25 – 30 cm
Origin: South America
Water temperature: 26-28 ° C
Aquarium volume: 300 l

Uaru amphiacanthoides (Uaru amphiacanthoides ) – an interestingly disposed aquarium fish from the cichlid family, resembling the popular discus in appearance and behavior. The species was first described in 1840 by J. Heckel. The name Amphiacanthoides was given because of its similar shape to the once-named Amphiacanthus sea fish , now synonymous with Siganus . Decades ago, when paddles were rare and expensive, Uaru was an interesting and cheaper alternative for them.

These fish are also a food source for people living along the Amazon basins.


Occurs in South America. It lives in small herds, mostly in the warm black waters of the Amazon and its tributaries.

Characteristics and disposition

In an aquarium, they reach 25-30 cm in length , in the natural environment up to 35 cm. The body is laterally flattened, this characteristic disc shape in nature makes it easier for them to move between sunken roots and branches.

The body color of Uaru adults is chocolate brown, with a distinctive black triangular point on both sides below the sideline. The iris of the eye is orange, greyed on the top, which looks a bit like an eyebrow. The mouth is equipped with small teeth. All fins, except the pectoral fins, are black and often have iridescent blue lines at their edges, especially visible on the dorsal, anal and ventral fins. During the breeding season, the sides of the body turn black, leaving only a little bit of brown around the edges.

The eyes also change from ordinary to copper red, which give the impression of fiery. In adult fish, the ends of the dorsal and anal fins are pointed, and in young ones, they are rounded. The color of the body of the young is brown with white spots. This pattern fades with age and becomes the color of adults. Usually, this interesting change occurs when they are about 5-7 cm long.

Gender difficult to distinguish. A fatty hump may appear in mature males. It is also believed that red eye color only appears in females. One hundred percent certainty about their sex can only be obtained from a thorough examination of their sex glands. It is recommended to keep a pair or a group of fish in the aquarium.

Held in greater numbers, they determine dominance hierarchies. Usually the herd is ruled by the alpha male, until another male wants to take over his role, then there are frequent fights between them. A group may also include an excluded, isolated and frequently attacked by other fish.

Nutrition and feeding

Omnivorous and unrefined, but plant foods should form the basis of their diet . In their natural environment, they eat plants, fruits, shellfish and detritus.

In the aquarium, you can give them good-quality dry foods with spirulina and those intended for discus. Additionally, you can serve carrots, green parsley, bananas, zucchini, watermelon, dandelion leaves. Plant-based foods are less polluting than animal foods and are lighter on fish. Shrimps are also a good and light food, which additionally enhances their coloration. An important element of the aquarium decor is wood , which should not be missing in the aquarium.

Uaru scrape them with tiny teeth, and it supports their digestive system.


For a couple, it is recommended to min. 300 liter tank, preferably 500 liters and larger. Its decoration best reflects their natural environment: soft sand at the bottom, a few pieces of wood and flat stones that can be selected by the fish to lay eggs. Plants should be omitted, as sooner or later they will be consumed.

Lighting should not be too bright. The water current must be strong enough to filter the entire volume of the aquarium at least several times an hour. The aquarium should be properly covered to prevent them from popping out, frightened ones can easily break even thin glass. Uaru are very shy, while approaching the aquarium or when cleaning, we should be careful because they can get panic attacks and hit the wall of the aquarium. For this reason, it is worth adding to them company in the form of other fish, e.g.

larger cuiras, armored fish or earth-eaters. The presence of other fish will give them more daring and courage. They prefer warm water 26-30 ° C, soft, close to neutral pH 6.5, but can adapt to slightly harder and alkaline water. Due to the large appetite and fast metabolism, they require efficient filtration and regular water changes, even up to two times a week.


The key to the success of breeding this species is, first of all, obtaining a matched pair .

For this purpose, it will be necessary to purchase a group of young fish (6-8 pcs.), Preferably from different sources. When they reach a size of about 20 cm, they will start to form pairs naturally. The obtained pair should be transferred to a separate breeding aquarium with many hiding places, where the female will possibly find shelter from too intrusive male. There should be flat stones in the tank as potential spawning grounds. Soft water is required for reproduction, it is recommended to use RO water, enriched with mineral salts, filtered through peat, at a temperature of 30-32 ° C.

A pair ready for spawning chooses a place to lay eggs, most often it is a flat stone, which the fish thoroughly clean with their tiny teeth (a characteristic scratching sound is then heard). The female spawns in a row which the male then fertilizes. An adult female can lay from 100 to 400 eggs – their number depends on the health, size and age of the fish. At a temperature of 28-30 ° C, hatching takes place within 48 hours. The hatched fry are moved by the parents to some quiet, sheltered place.

This is usually a dug basin in the ground. When the fry use up the yolk sacs, they begin to collect a special mucilaginous discharge on the parents’ skin. The waters in the natural environment of Uaru are poor in nutrients, therefore they have been endowed with this interesting method of feeding their offspring (similar to Discus fish). The diet of the fry should be enriched with e.g. brine shrimp larvae or micro nematodes, which will accelerate their growth.

Free-floating toddlers will be closely guarded by their parents. After approx. 2-3 weeks, the care disappears. At this point, you can separate the young from the parents. The fry should be fed several times a day in small portions, remembering about frequent water changes.

Well fed, after approx. 2 months, they will reach a few centimeters, and on average after approx. 1.5 years, they will reach sexual maturity. If a pair is unwilling to spawn, it can be encouraged in several ways. One of them is to change the decor of the aquarium, sometimes it is enough to add a new root or a piece of wood or rearrange the current decorations.

Fish for spawning can also be encouraged by changing the diet or changing the water to a softer and acidic water, or raising the temperature by 2-3 ° C. If these methods fail, you can try a more sophisticated approach. For about a month, you should stop changing water, lower its level to 1/3 of the tank height and feed sparingly. Then make 2-3 water changes (10-20% – very soft and acidic), at intervals of 2-3 days. Then make one more, in the amount of 2/3 of the aquarium volume, start feeding more generously, and increase the temperature to 31-32 ° C.

Young pairs that approach spawning for the first time usually eat the eggs or fry. That is why some breeders cover the eggs with a net until they hatch, and the hatched larvae separate them from their parents and raise them artificially. There are also those who collect eggs right after fertilization. However, it’s best to be patient and give the couple another chance to raise their young themselves.


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