This study investigates the concentrations of heavy metals and physicochemical properties of water, sediment, and African catfish (Clarias gariepinus) from earthen and concrete ponds used for aquaculture in Port Harcourt, Rivers State, Nigeria. Physicochemical analysis showed that water from earthen ponds had a pH of 5.60-7.52, salinity of 0.06-1.03 ppt, conductivity of 170-1671 μScm⁻¹, and turbidity of 38.71-163 NTU. In contrast, concrete ponds had a pH of 6.75-7.56, salinity of 0.18-0.71 ppt, and conductivity of 325-1442 μScm⁻¹, indicating differences in water quality. Water samples from earthen ponds exhibited cadmium (Cd) levels ranging from 0.013 to 0.187 mg/kg, lead (Pb) from 0.649 to 0.651 mg/kg, zinc (Zn) from 0.052 to 0.80 mg/kg, copper (Cu) from 0.009 to 0.158 mg/kg, and iron (Fe) from 1.198 to 4.112 mg/kg. In contrast, Concrete ponds showed Cd levels from -0.014 to 0.008 mg/kg, Pb from -0.0154 to 1.518 mg/kg, and Zn from 0.072 to 3.038 mg/kg. In earthen pond sediment, Cd ranged from 0.059 to 0.326 mg/kg and Pb from 0.505 to 1.160 mg/kg, exceeding permissible limits, especially at sites B and C, indicating contamination. Fish from earthen ponds had high heavy metal levels, with Cd from 0.175 to 22.433 mg/kg and Pb from 1.121 to 22.613 mg/kg, showing significant bioaccumulation. Conversely, concrete ponds had lower contamination, with Cd in sediment from 0.250 to 0.412 mg/kg and Pb in fish from 0.693 to 5.376 mg/kg, closer to safe thresholds. The results indicate significant contamination differences between pond types, with earthen ponds exhibiting higher heavy metal levels due to soil composition and exposure. In contrast, concrete ponds, which minimize soil-water interaction, showed lower metal presence in fish, highlighting a safer aquaculture environment. These findings stress the importance of continuous monitoring of earthen ponds and improved management practices to ensure consumer safety and sustainable aquaculture.