Betta ornaments are an exciting way to decorate your aquarium. With something for all tastes, they are an affordable way to enhance your display using fish-safe materials suitable for coldwater and tropical set ups.. Betta small grey rock formation is a natural looking resin ornament for all aquariums. It is a cluster of rocks with some decorative plastic plants attached. This is great for small fish to either swim through, hide and even breed in.. Approximate dimensions 13cm l x 6cm w x 8cm h .