Freshwater ray data sheet
German name:
freshwater ray
Scientific name:
Potamotrygone
Origin:
South American rivers
Size:
25cm – 100cm diameter
Aquarium
Length:
Length from 200 cm width and from 60 cm width
Contents:
from 2,000 liters
water values
Temperature:
25°- 30° C
pH:
6.5 – 7.5
GH:
8.4° – 15° dH
Behave
Area:
Floor
Lining:
carnivore
Behave:
do not socialize with other fish
Number:
small group
Difficulty level:
Advanced Marcel Burkhard, Stingray, CC BY-SA 2.0 DE
The ray belongs to the cartilaginous fish family and therefore does not have a swim bladder. When the ray wants to come to the surface of the water, its pectoral fins, which look like wings, support it. In addition, he usually has fat deposits, which also provide a boost.
Look
Its pectoral fins are united to the head and the body is extremely flat in shape. The mouth, gills and nostrils are found on the underside of the animal, while the eyes are on the upper side. Some species of freshwater ray have one or more poisonous stingers on their tails, so work in the aquarium should not be carried out with bare hands. A ray’s coloring can vary as these fish are excellent at adapting to their environment. In addition, the size is also very different, depending on which type of freshwater ray is kept. It can be between 25 cm and 100 cm in diameter of the body (body disc). In addition, Potamotrygon grows throughout its life.
Origin
It is at home in South American rivers and inhabits the sandy or muddy ground here. Only in rare cases does the freshwater ray swim freely in the water.
food
Potamotrygon is a pure carnivore, thus a predatory fish. The food offered in the aquarium should consist of mussels, shrimp, snails and either whole or cut up fish. A large variety of food is important and, ideally, this should be offered frequently in smaller quantities than a large amount of food once a day. Uneaten food must be removed from the tank.
If the food is not accepted, parasites or other diseases can be responsible. It must always be ensured that a quarantine tank is available.
gender differences
The male freshwater ray has an appendage behind the genital opening. This is not present in females. Otherwise there are no optical distinguishing features.
breed
The sexual maturity of a female is around two years. During the mating ritual, which can last up to 30 minutes, a male will sometimes bite the female’s body or fins. Otherwise, both lie with the stomach sides to each other. If the biting behavior is too violent, the fish must be separated from each other and injured females cared for in a separate tank.
A female ray bears about three months before the young are born alive. It is possible that only one baby is born, but more than 12 fish can also be born. The age of the mother animal plays a major role here. The offspring are independent immediately after birth and are hardly or not at all cared for by their parents. A size of up to 15 cm is possible for the young fish. In addition, the young should be raised in their own aquarium, as it is not unlikely that they will be eaten by the parents. The breeding tank can be significantly smaller than the home tank.
socialization
It is better not to socialize with other fish. The freshwater ray is a predatory fish and will eat anything it can fit in its mouth. It is also possible that larger fish are killed but not eaten.
Other Questions
How should the aquarium be equipped?
The most important thing here is the base of the pool. It should be borne in mind that in the trade mostly young fish are offered and they grow for a lifetime. The dimensions given in the table above are sufficient for two freshwater rays. Approximately 20% of the floor area should be added for each additional animal. The water depth is not important here.
If the aquarium does not have a cover, the upper edge must have a so-called edge bridge, or the water level must end about 15 cm below the upper edge. Potamotrygon likes to surface and may fall out of the pool.
The lighting and any existing heating element should be provided with a protection so that the ray cannot burn itself.
The substrate should consist of river sand so that the animals can dig in and dig in. Some structures made of rocks and roots as well as larger pebbles serve as a privacy screen and as a retreat. Planting is also possible. This makes the most sense on the rear pane in the form of tall and vigorous species. However, all structures in the tank must be at a greater distance from each other so that the ray can move easily between them.