Green sea mat (Zoanthus sociatus) care guide

Group
Corals
Other names
Zoanthids, Zoas, Button polyps, Sea mat
Family
Zoanthidae
Origin
Western Atlantic and Caribbean, from Florida and Bermuda to Brazil; shallow reef flats
Water
saltwater
Temperature
22–26°C
pH
8.1–8.4
Hardness
dKH 8–10
Care level
beginner
Reef safe
yes
Lighting
Low to moderate; about PAR 80–150
Flow
Moderate, indirect

Care

Zoanthus sociatus is a zoanthid: a mat of small, round polyps joined at the base, each with a ring of short tentacles around an oral disc. In the wild it is mostly green. In the hobby, Zoanthus are sold under hundreds of morph names, such as "Bowzer" zoanthids. Place it low to mid on its own rock island so its spread can be controlled. LiveAquaria lists Zoanthus as easy in care, with moderate light and low to moderate flow; Top Shelf suggests PAR 80–150, raised over 2–3 weeks, and moderate indirect flow to keep detritus off the mat. Water: LiveAquaria gives dKH 8–12, pH 8.1–8.4 and 22–26 °C, with iodine and trace elements; Top Shelf suggests calcium 400–450 ppm and steady salinity, since zoanthids dislike fast swings. Very low nutrients can make them recede. Safety: zoanthids and palythoa can contain palytoxin, a dangerous toxin. Wear gloves and eye protection when handling or fragging them, and never boil, scrub or pressure-wash rock that carries them. Not CITES-listed. Sources: LiveAquaria (liveaquaria.com/products/colony-polyp-zoanthus-corals); Top Shelf Aquatics (topshelfaquatics.com/pages/corals/bowzer-zoanthids-coral). Checked October 2026.

Diet

Mainly photosynthetic. Fine foods such as zooplankton, rotifers, phytoplankton or coral powders once or twice a week can help growth. Feed more if lighting is weak.

Breeding

Very easy. Polyps multiply by budding. Cut a group of polyps from the mat with a scalpel or snip a piece of the rock, then glue it to a plug with cyanoacrylate gel. Wear gloves and eye protection.

Compatibility and tank mates

Semi-aggressive in a mild way: short sweepers can sting nearby polyps, and colonies can overgrow slower corals. Top Shelf suggests 5–10 cm of space. Some angelfish and butterflyfish eat zoanthids.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

About Aquatic-Auctions

  • Aquatic-Auctions (aquatic-auctions.com) is a UK online marketplace for aquarium and pond livestock and equipment: tropical and marine fish, corals, shrimp, snails and other invertebrates, aquatic plants, tanks, filtration, lighting and food.
  • Items are sold by auction, buy it now or classified advert, by hobbyist and business sellers in the UK.
  • Buyers pay sellers directly; Aquatic-Auctions does not hold the money. Hobbyist sellers must offer PayPal and may also take cash on collection. Business sellers take PayPal (required) or cash on collection, and bank transfer only once they have a seller rating of 50 out of 100, a company and pet-selling licence checked by Aquatic-Auctions, a bank account in the company's name, and bank details approved by Aquatic-Auctions.
  • Buyers are told to pay by PayPal Goods & Services, never PayPal Friends and Family, gift cards or crypto.
  • Live fish and other vertebrates must be sent by specialist live-animal couriers (for example APC Overnight or DX Express), never by Royal Mail. Some invertebrates and plants may go by Royal Mail Special Delivery or 1st Class within its rules.
  • Banned and invasive species (for example those on the GB invasive species lists) cannot be listed, and sellers must meet the site’s animal welfare standards.
  • Members must be 16 or over to buy (16 and 17-year-olds with a parent or guardian’s agreement); sellers must be 18 or over.
  • Business sellers show their address, company details and pet-selling licence to buyers. Seller ratings run from 0 to 100: +1 for each positive feedback, −1 for each negative.
  • The site includes a free community species wiki with care guides (water parameters, tank size, diet, temperament, breeding).
  • Aquatic-Auctions is run by Etavonni Tech Limited trading as Aquatic-Auctions (company number 10204188), Aldershot, Hampshire, UK. Contact: info@aquatic-auctions.com.