Pearl Freshwater Stingray

Potamotrygon signata is endemic to the Parnaíba River basin in Piauí and Maranhão states of northeastern Brazil — a completely isolated river system, separate from both the Amazon and coastal Atlantic drainages of the country. This biogeographic isolation has produced a morphologically and genetically distinct species with a strongly spotted pattern of dense pale spots on a brownish disc. Its restricted range and legal protection in Brazil mean that specimens virtually never appear in the trade through legitimate wild-caught channels; all available individuals are captive-bred, usually sourced from a small number of specialist European breeders who maintain founder populations. Water quality requirements are standard for the genus, though some breeders note that slightly warmer temperatures favour reproduction.

Water: 24–28°C, pH 6.0–7.0, soft (2–8 dGH); zero ammonia/nitrite; consistency of parameters is paramount. Tank: Minimum 400L, fine sand, no calcareous substrate; adequate lighting to observe the animal without causing stress. Feeding: Carnivore; earthworms, prawn, mussel, frozen bloodworm; established individuals eat reliably. Breeding: Viviparous; captive breeding essential for species preservation; small litters of 2–5 pups. Compatibility: Large, calm fish only; minimise competition for food given scarcity of individuals.