Animal field guide
Zoanthid
Zoantharia
Zoanthid teaches Held Ground as a mat rather than a monument. No single polyp is much, but a colony spreads across bare rock, closes ranks when disturbed, and defends its patch with chemistry instead of size.
AnimalDex card
Unlock this animal card
Scan or capture this animal with AnimalDex to reveal its collectible card and add it to your wildlife collection.
Get AnimalDexZoanthid at a glance
Animal · Native range keys: indian_ocean · Whole colony closes at once when · Relatively common
Known for: Colonies of small polyps, Polyps joined at the base by a shared mat of tissue, Whole colony closes at once when disturbed, Extremely variable colour
Understand the animal
Understand the Zoanthid
Factual biology first: what this animal is like, where it lives, how it survives, and why those traits exist.
01
Introduction to Zoanthid
Zoanthid teaches Held Ground as a mat rather than a monument. No single polyp is much, but a colony spreads across bare rock, closes ranks when disturbed, and defends its patch with chemistry instead of size.
How to identify a Zoanthid
- Colonies of small polyps, each a disc of tentacles 5-20 mm across
- Polyps joined at the base by a shared mat of tissue
- Whole colony closes at once when disturbed
- Extremely variable colour, often ringed in contrasting bands
Why Zoanthid are interesting
- Many zoanthids carry palytoxin, among the most poisonous non-protein substances known, and aquarium keepers have been hospitalised handling colonies in a closed room.
- Polyps in a colony are connected by a shared tissue mat, so the colony behaves as one animal.
- Palythoa and Protopalythoa embed sand grains in their tissue, which makes them tougher than they look.
- Symbiotic algae in the tissue supply much of the colony's energy.
- The colour morphs sold in the aquarium trade are variants, not separate species.
02
Adaptations and biological abilities
03
Why does Zoanthid behave this way?
- Colonies of small polyps, each a disc of tentacles 5-20 mm across
- Polyps joined at the base by a shared mat of tissue
- Whole colony closes at once when disturbed
- Extremely variable colour, often ringed in contrasting bands
Zoanthids have no sleep in the animal sense, but polyps open in good light and current and close tight at night or when disturbed, so a colony visibly changes shape through the day.
04
Why Native range keys: indian_ocean?
Habitat: Native range keys: indian_ocean, south_pacific, coral_triangle, north_atlantic. Shallow, well-lit reef flats, rubble and rock walls with steady water movement suit Zoanthids because Held Ground needs hard surface to spread across and current to feed on.
Native range: Native range keys: indian_ocean, south_pacific, coral_triangle, north_atlantic. Shallow, well-lit reef flats, rubble and rock walls with steady water movement suit Zoanthids because Held Ground needs hard surface to spread across and current to feed on.
Native range
Natural range, not this specific capture location.
Some regional overlays are unavailable in this web build.
Native range keys: indian_ocean, south_pacific, coral_triangle, north_atlantic. Shallow, well-lit reef flats, rubble and rock walls with steady water movement suit Zoanthids because Held Ground needs hard surface to spread across and current to feed on.
05
Why this diet?
Sugars from symbiotic zooxanthellae, plus plankton and particulate matter caught by the polyps. This diet supports Held Ground because a colony fed by light and current does not need to move to eat — it only needs to keep its rock.
06
Activity, rest, and lifespan
Zoanthids have no sleep in the animal sense, but polyps open in good light and current and close tight at night or when disturbed, so a colony visibly changes shape through the day.
Colonies persist for many years and keep spreading, so Held Ground compounds — every season adds rock the colony did not hold before.
07
Zoanthid reproduction
Colonies grow mainly by budding new polyps off the shared mat, and also spawn into the water column. Offspring fit the principle because most new polyps are simply the colony extending its own edge.
Polyps show no external difference between sexes. Appearance carries no signal because the colony spreads mostly by budding rather than by pairing.
08
Predators, threats, and defense
Nudibranchs and a few specialised snails and butterflyfish. Its answer is chemical: palytoxin makes a colony a poor meal, and the whole mat closes at once when something touches it.
09
Conservation and rarity
Rarity: Relatively common · 36/100. AnimalDex canonical rarity score: 36/100, maintained by the live indexed species profile.
- Observe from a respectful distance and avoid changing the animal's behavior.
- Do not block feeding, shelter, nesting, or travel routes.
- Use a live camera capture without handling or staging wildlife.
Ask AnimalDex
Ask AnimalDex about the Zoanthid
Ask about its biology, behavior, abilities, survival strategy, symbolism, or what its strategy can teach you. Answers stay grounded in this species page.
Anonymous: 3/day. Signed-in: 10/day. Pro: 30/day fair use.
Compare
Compare the Zoanthid
Where to find them
Where to find Zoanthid
To find Zoanthid in the wild, focus on the exact habitat patches that match its body design and daily behavior, not just the broad country where it exists. You usually do better by working one good piece of habitat inside native range keys: indian_ocean, south_pacific, coral_triangle, north_atlantic. Shallow, well-lit reef flats, rubble and rock walls with steady water movement suit Zoanthids because Held Ground needs hard surface to spread across and current to feed on. than by covering too much ground.
- Headlands, reef edges, island colonies, tidal channels, or productive coastal water
- Burrow systems, sandy banks, fallen logs, or ground with clear den entrances
- Protected habitat blocks within native range keys: indian_ocean, south_pacific, coral_triangle, north_atlantic. Shallow, well-lit reef flats, rubble and rock walls with steady water movement suit Zoanthids because Held Ground needs hard surface to spread across and current to feed on.
Animal field guide
Zoanthid
Zoanthid teaches Held Ground as a mat rather than a monument. No single polyp is much, but a colony spreads across bare rock, closes ranks when disturbed, and defends its patch with chemistry instead of size.
Native range
Natural range, not this capture location
Native range keys: indian_ocean, south_pacific, coral_triangle, north_atlantic. Shallow, well-lit reef flats, rubble and rock walls with steady water movement suit Zoanthids because Held Ground needs hard surface to spread across and current to feed on.
Search near meAnimalDex stats
Dominance
24
Speed
3
Size
8
Intelligence
6
Rarity
36%
Total
77
Size scale
Scientific name
Zoantharia
Category
Animal
Habitat
Native range keys: indian_ocean, south_pacific, coral_triangle, north_atlantic. Shallow, well-lit reef flats, rubble and rock walls with steady water movement suit Zoanthids because Held Ground needs hard surface to spread across and current to feed on.
Rarity
Relatively common · 36/100
Native range
Native range keys: indian_ocean, south_pacific, coral_triangle, north_atlantic. Shallow, well-lit reef flats, rubble and rock walls with steady water movement suit Zoanthids because Held Ground needs hard surface to spread across and current to feed on.
Take the encyclopedia outside
AnimalDex helps you scan real animals, identify species, collect cards, and learn from nature wherever you are.