Teacup Stingray

Potamotrygon wallacei is the smallest known freshwater stingray, reaching only around 30cm disc width at full maturity, from the Rio Negro and its blackwater tributaries in Brazil. Its disc is dark brown to almost black, covered in vivid yellow to orange spots, giving a striking contrast that belies its modest size. The common name 'teacup' refers to the small adult size rather than ease of keeping — this species is among the most demanding, requiring true blackwater conditions with pH as low as 4.5–5.5, very low TDS, and extremely soft water. Any deviation from these conditions can cause rapid health decline. It is bred in captivity by European and Asian specialists with appropriate RO and blackwater conditioning systems. A spectacular but uncompromising challenge.

Water: 26–30°C, pH 4.5–6.5, extremely soft (0–3 dGH), low TDS; RO water with blackwater extract mandatory. Tank: Minimum 300L, very fine dark sand, tannin-stained water; no calcareous rocks or shells; tight lid. Feeding: Carnivore; live or thawed bloodworm, small earthworms, tiny diced prawn; small and frequent meals. Breeding: Viviparous; tiny litters of 1–4 pups; blackwater conditions essential for successful reproduction. Compatibility: Specialist blackwater setup; companion fish limited to large, acid-tolerant species.