Perth's best aquarium products shop with fish tanks, eheim, jager, Oceanson, pumps, heaters, lighting, texas holey rock, accessories, ornaments, etc ... (crushed corals) AU$18.00. 10kg 2-5mm Aquarium Gravel. AU$22.00. AU$16.00. 13kg Bags of 3-7mm Black Aquarium Gravel. AU$24.00. AU$17.00. Aragonite - Premium Pacific Crushed Corals 5kg.