Zoanthids, also called zoas, button polyps or colonial anemones, are a hardy and diverse Order of coral that are suitable for beginner, intermediate and advanced aquarists. They are tolerant of a range of aquarium conditions, come in unbelievable bright color morphs and many of them grow very quickly. There are three general growth forms associated with this order.
Some species have freely growing separate polyps. Other species have polyps that are joined loosely at the base by a sliver of tissue called a stolon, whereas the third growth form of zoanthids have polyps that are actually integrated deep into a fleshy tissue called the coenchyme. That really only matters if you are an uber aquarium geek or a taxonomist. From the perspective of zoanthid care in the aquarium, there really isn’t much of a difference but if you see corals listed as zoanthus, palythoa, or protopalythoa, just know that the differences, among other things, have to do with whether or not the individual colonial polyps are attached to each other at the base.
If you really do want to learn more about the differences between the classifications, you can read more about that here.
The majority of zoanthids have symbiotic photosynthetic zooxanthellae (I dare you to try and say that three times quickly) and are therefore best kept with at least moderate aquarium lighting. Some of the more brightly colored morphs will tolerate even intense lighting from metal halide or newer generation LED lights if acclimated properly.
Most species are capable of actively capturing prey. For fastest growth of these coral, it is recommended that you feed them periodically with an appropriately sized food, although feeding is not usually required.
Target feeding these coral polyps is fairly straightforward, you simply place food particles that are the right size as close to the center of the polyp as you can. The Polyps will fold inward, the mouth will open, and the food will go inside. This is the fastest and best way to grow these corals. Don’t forget that corals are animals–and animals like to eat. Yes, they can and do get some of their energy from the symbiotic zooxanthellae that live inside their tissue, but that is only half of the story. You will be rewarded with strong growth if you feed them regularly.
If your zoas won’t eat, try changing up the size and type of food you are offering. Borneman reported that some zoas would only respond to certain food prey items.
Troubleshooting problems: zoanthids not opening
Some of the more rare and delicate zoanthids may take a couple of days to open up after transportation to your home. If you just bought your polyps, don’t worry if they won’t open up right away. However, if your polyps were previously open and have recently closed up, this should be taken as a serious sign of a water parameters issue. The first things I would check are salinity and pH. In my experience, zoas will close up if there are swings in salinity. I originally read about this in the book: Practical Coral Farming.
Zoanthids for sale
You will find zoas for sale at any respectable local or online fish store. Prices will vary for just a few dollars ($5-10) for a small frag all the way up to the max you will want to pay for a high-end designer coral with a fancy name like Orange bam bam zoanthids or purple hornet zoanthids, which can sell for $100 or more for every coral polyp.
Top Zoanthids to Buy
One of the most fun aspects of keeping zoanthids in your saltwater aquarium is to collect polyps from the hottest color morphs. They have ridiculous sounding names that seem to make perfect sense once you see them. If you’re just getting started, here is a list of some of the names you can start with to begin your search to find the perfect zoanthid for your saltwater aquarium.
- Fruit Loops
- Purple People Eater
- Orange bam bam zoanthids- long tentacles and rapid growth
- Purple hornet
- Blueberry field zoanthids
- Fire and ice zoanthids
- Whammin’ watermelons
- Sunny D’s
- Red Hornets
- My Clementines
- Blue Hornet
- Radioactive dragon eyes
- Utter chaos
- Blue Agaves
- Night Furies
- Captain Americas
- Candy apple reds
To see what some of these zoanthids look like, take a look at this eye-candy video with a ranking of the top 10 most popular zoanthids.
Over the last few years, there has been a bit of a zoanthids collector mania, driving up the prices of rare zoanthid color morphs. These rare zoanthids go
by names like bubble buster, tazer, tyree space monster and bloodshots. These corals are for the ultimate collectors with a lot of money, dreams of coral propagation and an I gotta have it gene. These corals are so expensive and so popular there are forum threads that discuss the street value of these corals. You can’t make that stuff up.
Several species of zoas produce a toxic chemical, called palytoxin, and so individual specimens should be handled with extreme care. Palytoxin can cause neurological damage if it gets inside of a cut, your eyes or in your nose or mouth. Always wear protective gear when handling zoanthids, including gloves and goggles. Not every variety of zoanthid creates palytoxin, but be sure to let friends and family members know about it, just in case you ever run into an issue. A great way to do that is to document the issue in the back of your reef journal and to let your family know it is there.
Diseases: Zoa Pox
One disease that seems to disproportionately impact zoanthids is something called zoa pox or zoanthid pox. Zoa pox is the name given to the zoanthid disease characterized by tiny growths on the side of the affected zoas. I’m not sure whether the growths/pustules themselves irritate the polyps and cause them to close up, or if the coral is otherwise sickly and closed up (therefore showing the zoa pox), but the bottom line is that if you see zoa pox, you have a sick coral.
If you are interested in hardy, fast-growing, brightly colored corals (and who isn’t?) then there is probably a perfect zoanthid for you. Be sure to wear protective gear and always wash your hands when handling them and most of all, take pictures and enjoy.