Zoo Med Sinking Resin Aqualog The Zoo Med Sinking Resin Aqualog offers shelter to all aquarium fish. This log is manufactured with 100-percent plant resin, and provides excellent surface for beneficial algae growth. The Naturalistic looking log offers shelter for all shy fish such as catfish, knifefish, eels, some cichlids and more. Features: Made from 100-percent plant based, resin.