Koralle isn’t just a pretty name for a rock on the ocean floor. It’s the largest class of cnidarians, boasting roughly 6500 living species. That’s a lot of biodiversity packed into one taxonomic group. You might not realize it, but 20 of these species call the German coastline home. They’ve been there a long time. We also know of 5000 extinct fossil species that walked—or rather, swam and settled—the ancient seas.
The scientific name Anthozoa literally means “flower animals.” It’s a fitting title. The vibrant colors and intricate shapes mimic terrestrial blooms. This visual similarity tricks the eye. It tempts you to classify them as flora.
But look closer. The distinction matters.
Not Plants. Not Rocks. Colonies.
Korallen attach themselves to the seabed. They sit there, seemingly passive, rooted in the substrate. This immobility is the primary reason people confuse them with plants. Plants don’t run away from predators. Neither do corals.
The difference lies in biology. A coral “rock” is actually a massive, branching structure composed of thousands of individual organisms. Each polyp is a distinct animal. They are colonial. They work together, often in symbiosis with algae, but the structural unit is animal tissue, not cellulose or vascular systems.
Traditional criteria separate animals from plants. Mobility is the usual standout feature. Animals move. Plants generally do not. Corals break this rule in their adult form. They are sessile. Yet, they are undeniably animals. They feed on plankton. They sting prey. They reproduce sexually. They are not photosynthetic engines like kelp or seagrass.
What About the Jewelry in Your Ring?
When you see a deep red coral in a jewelry store, you’re looking at a skeleton. Specifically, it’s the calcified exoskeleton of gem corals (Edelkorallen ). These aren’t the same delicate, living polyps that build vast reef ecosystems in tropical waters. These are dense, slow-growing organisms found in deeper, colder waters.
The material is calcium carbonate. Hard. Durable. Beautiful. But it’s dead matter extracted from a living animal.
Why This Distinction Matters
Understanding that corals are animals changes how we view their conservation.
- Fragility : If you break a coral branch, you aren’t snapping a twig. You’re killing thousands of individual animals.
- Symbiosis : Most reef-building corals host zooxanthellae (algae) within their tissues. This relationship provides up to 90% of their energy needs.
- Threats : Bleaching isn’t a plant wilting. It’s an animal expelling its symbiotic partners due to stress. The coral doesn’t just look sick; it’s starving.
The 20 species along the German coast, such as the black coral (Leiopatha ) or various sea anemones (closely related), highlight that this isn’t just a tropical phenomenon. The North Sea and Baltic Sea host their own hardy, cold-water counterparts.
The Bigger Picture
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