Aquarium Decor is made from top quality resin material, non-toxic, no smell. Resin Aquarium Decor is lightweight, but it is flat and heavy enough to stand steadily in your tank, fits for salted water and fresh water. Attention: This Fish Tank Aquarium Decorations doesn't produce algae, Usually algae are caused by light. Artificial Resin Fish Tank Landscape Ornaments' Volume is 4.3"(L) x 4.1"(W) x 6.9"(H), apply to all fish tanks larger than this volume, but please pay attention to the proportion of aquarium décor and Aquarium.