Freshwater rays are very sensitive to ammonia, nitrites, and nitrates content in water, that’s why it is important to have an understanding of a nitrogen cycle and keep the tank water crystal clear.
The latter is quite a challenging task since rays produce a large amount of ammonia. Large-sized tanks, efficient biological filtration, and regular water renews – is the only way to keep the proper tank and water conditions.
Most freshwater rays can be kept in a tank at PH from 6,8 to 7,6, alcalinity from 1° to 4° (from 18 to 70 ppm) and water temperature from 24 to 26°C. Ammonia and nitrites level should be zero, and nitrates level should be lower than 10 10 ppm.
In terms of the tank size for rays, the following approach works best – the larger, the better. The walls height is not a crucial parameter, but the tank should be from 180 to 220 cm long and from 60 to 90 cm wide to keep a ray in it for a long time.
A tank from 350 to 500 liters capacity will do to keep young rays in it, but for a long-term keeping of adult species, you will need a tank not less than 1000 liters large. Small-grained sand can be used as the tank substrate.