The delicate one. A seaweed that looks like it belongs in a window, not on a reef. Red lace algae grows flattened, branching, finely divided fronds with a lace-like or net-like appearance. The colour is a beautiful pinkish-red, sometimes with purple highlights. Fronds are soft and flexible, waving gently in the current. It looks like something that might be hung in a window, not something that grows on a rock. A plant that belongs in a craft shop. What makes it special is the defence. Soft and delicate, a tempting meal for any hungry sea creature. But it has a secret weapon. It produces chemicals called furanones that deter grazing by sea urchins, fish, and other herbivores. These chemicals interfere with the ability of bacteria to communicate with each other. The algae is not just defending itself; it is also preventing bacteria from settling on its surface. A plant that fights with chemistry. Reproduction happens by releasing spores from specialised structures on the fronds, produced in small, raised bumps on the surface. Red lace algae provides habitat for small invertebrates. Tiny crustaceans hide among its fronds. Small snails graze on its surface, but they are careful – the chemical defences make it a less appealing meal. A plant that shelters others while protecting itself. To find red lace algae is to find a piece of living lace on the reef. Fronds are delicate, beautiful, almost fragile. But they are tough in their own way, armed with chemical weapons that keep grazers at bay. The reef is quiet. The red lace waves in the current, pinkish-red and delicate. A sea urchin approaches, then turns away. The chemicals warn it off. The algae does not need to be tough. It just needs to be unappetising. And that is enough.