Citizen-Science Records Identify Al-Badi'ah and Namar Urban Lakes as Potential Aquarium-Release Hotspots for Non-Native Aquatic Organisms in Riyadh, Saudi Arabia

Urban freshwater systems in arid regions may function as focal points for the release and establishment of unwanted aquarium organisms, yet such pathways remain poorly documented in Saudi Arabia. This short communication integrates georeferenced citizen-science observations with publicly visible aquarium-trade and hobbyist signals to evaluate two urban water bodies in Riyadh—Al-Badi'ah Lake and Namar Lake—as potential aquarium-release hotspots. Two photograph-supported iNaturalist records of suspected non-native crayfish were retained (observations 264920283 and 265181171), approximately 3.90 km apart, with public coordinates corresponding provisionally to the Al-Badi'ah and Namar urban-water network. A nearby iNaturalist observation of a putative red jewel cichlid (Rubricatochromis sp.; Needs ID) occurred approximately 50 m from the first crayfish record, providing a second, taxonomically independent signal of an aquarium-associated introduction pathway. Publicly visible trade and hobbyist content further documented crayfish availability in Riyadh and Jeddah, including platform-reported Australian redclaw and dwarf Mexican crayfish. These evidence streams do not demonstrate establishment, reproduction, or ecological impact, and species-level identification of the crayfish remains unresolved. Instead, they identify publicly accessible urban lakes where targeted field verification is warranted using standardized trapping, fish surveys, environmental DNA, voucher specimens, and DNA barcoding. The study proposes a precautionary framework for distinguishing captive-trade evidence, suspected outdoor occurrence, and confirmed establishment, thereby supporting proactive surveillance of aquarium-mediated introductions in Saudi Arabia.