Several weeks ago, a reefing buddy called to complain about his tank. I’ll spare you the boring details and get right to the point.
His tank isn’t as attractive as he wants.
As I sat and listened, his disappointment and frustration felt too familiar. When he finally ran out of steam, I gently asked what coral species he’s growing. Annoyed by my seemingly lack of empathy, he continued his rant.
After a while, I decided to interrupt with the same question. But this time, I changed the wording.
Author:
As a lifelong aquarist, Yuliya has an endless curiosity about our underwater universe. After graduating with a bachelor’s in Environmental Engineering, she transformed her passion into a successful career. While working at the Institute of Environmental Protection in Moscow, her passion for saltwater and reef aquariums only increased. Moving to the United States in 2013, Yuliya embarked on another impactful journey by sharing her unprecedented experience for all aquarium hobbyists ... Read More.
“Have you thought about growing Zoanthids?” He grew silent, and followed this question with one of his own, “What’re those?”
It was my turn to monologue. But instead of complaining, I spent the next 30 minutes explaining the benefits and value of this popular coral.
That’s when it hit me.
If he didn’t know what Zoanthids were, or how they can turn a tank from boring to brilliant, how many others are like him? How many of my fellow reefers don’t know that not only are Zoanthids visually stunning, but incredibly simple to raise?
The challenges of reef keeping aren’t limited to water chemistry and technical metrics. For millions, the challenge is knowing what species to use and how to visually enhance their tank. Are you dissatisfied with your tank appearance? Have you followed the hacks in our aquascaping guide, but still haven’t reached the look you imagine?
Maybe it’s time to stop researching design tips and start thinking about coral variety, more specifically, Zoanthids. Popular among new and professional reef keepers, this coral species adds a hefty dose of visual magic without complicated care requirements.
In my opinion, Zoanthids are some of the best corals for novice reefers. But what are they? Why are they revered by so many reefers as a must-have species? Let’s dive into the colorful world of what may become the newest member of your reef tank family.
Introducing Zoanthids: The Sea’s Beautiful Colonizers.
If you’ve browsed one of the many reefing forums, you’ve probably read about this vivid coral. New and experienced reefers are obsessed with Zoanthids, or more commonly called, Zoas. So what’s the big deal? Why are countless forum threads, blog posts and books written about this specific coral?
Like most things in our hobby, the best way to understand why something is popular is to investigate its origins. In the case of Zoas, let’s take a brief journey into the biology of this widespread coral. Don’t worry, you didn’t stumble into science class. We’ll keep this part quick.
First, Zoanthids aren’t actually coral. I know, this doesn’t make sense. If they aren’t coral, why am I and every other reefer calling them by this name? In all honesty, I’m not sure. But, that’s what it is. So what are they? Zoas are officially categorized as cnidarians and are referenced by the scientific community as colonial anemones. This is because of their tube-like shape and wide array of sizes and colors.
What I find most interesting about Zoas is how common they are in a variety of marine environments. Unlike other species, they’re not restricted to only tropical reef environments. Instead of being locked to a specific ecosystem, Zoas are found throughout the world in both shallow reefs and in the deep sea. When I first learned about this, I immediately knew this species isn’t a dainty lady. Any species capable of growing in so many different locations is one tough fella.
Unlike other colonizing anthozoans or soft corals, Zoas create their structure with small pieces of surrounding materials, like sand. This helps strengthen their bond and sturdiness to environmental influences.
Colonies are made of individual polyps, which join together to work as a community. Think of them as a living apartment complex. On the outside, they look like one unit, but it’s actually a massive collection of individuals living together.
Zoas are asexual, which means they reproduce from themselves. Interestingly, offspring don’t float away to start their own lives. They remain connected to the original polyp for life. Kinda like that one friend who refuses to move out of their parent’s house.
Now that we’ve got that covered, how can you identify Zoas? Since they’re part of a class and order of marine life that numbers in thousands, knowing how to distinguish harmless Zoanthids from harmful relatives is vital.
Zoanthid Taxonomy & Identification for Reefers.
Learning how to identify coral species and other marine life is tricky. Zoas aren’t any different. Thankfully, as long as you keep a few tips in mind, identification becomes much easier. While there’s many ways to distinguish Zoas from its relatives, here’s the most essential tips to know:
- Zoanthids may look like small sea anemones, but unlike anemones that live alone, Zoas tend to live in colonies like corals.
- Since they don’t grow hard skeletons, Zoa tissue is leathery.
- Typically, polyps feature a cylindrical body column that looks like a tube with a flat circular disk at the top. I like to think of this disk as its fancy hat. Stemming off this “hat,” are small tentacles, which are often distributed in two rows that rest close together.
- Its coloration can range, but generally Zoas feature a splash of color in the center of the disk that transitions into darker colors into the tentacles. The array of colors that Zoas come in is one of the top reasons why so many reefers flock to this species. Its multicolored design transforms dull aquascaping into works of art.
- Zoas exposed to stronger flow rates, or strong waves in the wild, are typically shorter and more spread out. Those living in calmer waters tend to develop taller bodies with longer tentacles.
- While the actual polyps tend to be on the small side, typically less than 1 inch, the colony can spread and grow at a rapid pace.
Photo by Bernard DUPONT / CC BY-SA 2.0
Poisonous Polyps - Are Zoas Toxic?
Now that we’ve covered what these creatures are and how to identify them, it’s time to answer the most important question: are they poisonous?
The last thing you want to do is introduce a toxic inhabitant in your carefully crafted tank. While Zoas are brilliantly designed and appear benign of danger, sometimes the prettiest creatures are the most dangerous. Although the majority of Zoas are harmless, some carry the most toxic poison found in marine life: palytoxin.
This defense mechanism intended to thwart predators is one of the most serious threats to your safety. Even the smallest quantity of palytoxin can result in paralysis, or worse, death. Needless to say, careful handling is absolutely necessary. Researchers think that the actual animal doesn’t produce palytoxin. Instead, it’s thought a bacteria living with the polyps is responsible for making this poison.
Regardless, you must always be careful when handling all types of Zoas.
Never handle a Zoanthid with an open cut or wound. More importantly, never touch your mouth or eyes without thoroughly washing/disinfecting your hands. Smart reefers minimize this risk by wearing thick gloves (I'm using the West Chester 2920 when fragging zoas) and taking extreme precaution whenever they must touch this beautifully dangerous coral.
Since you likely want to avoid encountering the most toxic substance known to humankind, what Zoas should you avoid? Here’s a list of known Zoanthid species hiding this fatal toxin:
- P. texaensis
- P. mammillosa
- P. gradis
- P. caribbea
- P. nigricans
If you aren’t sure what species you have, or will be getting, use precautions 100% of the time. Regardless if you’re handling species from the Zoanthus, Protopalythoa or Palythoa genera, always wear protective gloves, eyewear and even a face/breathing mask like 3M Cool Flow.
Whoever said beauty can be dangerous was right.
Zoanthid Care Hacks for Continued Health.
Unlike high school life, Zoas didn’t become popular only because of their beauty and attractiveness. While it may be what originally attracts reefers, it's their easy maintenance that’s the real star of the show.
New and experienced reefers enjoy the straightforward care requirements. While inhabitants enjoy the biodiversity Zoas offer. Here’s a list of the most essential care hacks and maintenance tips. Follow this guideline and you’ll soon enjoy a tank filled with vibrant and healthy Zoanthids.
Ideal Water Parameters.
Because of their hardiness, Zoas are fairly resistant to shock. However, even though they aren’t as delicate as a daisy, water parameters should remain as stable as possible.
In general, as long as your water parameters are stable/healthy enough to sustain other tank inhabitants, it should be acceptable to Zoas. Essentially, you’re shooting for standard tropical seawater levels, which average:
- Temperature - Anywhere around 78 degrees Fahrenheit.
- Salinity - Averaging roughly 1.026 specific gravity.
- Hardiness - 7 to 12 dKH Side note: I run all my tank at 7.0 - 7.3
- pH - Between 7.9 and 8.4.
Hacking water parameters is easier with the right equipment and tools. I recommend installing an RO/DI water treatment system, choosing a reputable reef salt mix and sure don't skip your water changes.
Feeding Hacks .
Sticking with the easy theme, feeding Zoas is relatively effortless. First off, Zoanthids have a photosynthetic partnership with Zooxanthellae. Because of this, lighting is very important, which we’ll talk about next. In case you aren’t familiar with photosynthesis as it relates to coral, it’s exactly what you learned in science class.
Plant cells absorb light energy, which is then transformed into food energy. While this natural energy conversion happens without much effort on your part, Zoas can’t survive on light alone. Well, they shouldn’t, at least.
Target feeding is exactly what it sounds like. Corals food is injected directly above the Zoas. The polyps fold inward and open their mouths for a luxurious meal. Remember, corals are both plant and animals. Light feeds the plant part, while actual food feeds the animal.
This type of feeding method is popular, but honestly, it’s a little too involved for my taste. Personally, I pour the recommended amount of food directly in front of the powerhead before the lights are scheduled to turn off.
How do I know they’re eating? Not considering the obvious fact that they’re still alive, but you know your Zoas have full belly’s when there’s a dark brown substance around them the next day or the day after that. What’s the substance? Well, what do you do after eating a giant meal?
Yes, it’s poop. Many people confuse it with the brown jelly disease.
It’s hard to imagine this type of marine creature could be a picky eater, but it’s true. If you find your Zoanthids not eating, you may need to change your food sources. There’s a lot of quality options on the market, but I recommend:
- Red Sea Reef Energy | A and Red Sea Reef Energy | B
- Polyp Labs Reef-Roids.
- Brightwell Aquatics Reef Blizzard-S.
Many reefers also like the Coral Frenzy `The Ultimate Coral Food`, but I didn’t get a chance to try this food yet.
Zoanthid Placement Hacks for Optimum Water Flow and Light Exposure.
Ideally, your Zoanthids should live in a low to medium-high flow area. If placed in too high of a flow area, polyps will have a difficult time opening, which stunts its growth/development.
How do you know if they’re happy? Don’t worry, they’ll let you know. When polyps are fully opened/extended without appearing to strain upright, then you’ve found the sweet spot.
Generally, Zoas prefer a location that’s neither too shaded or too exposed. Check the preferred lighting environments based on your species.
Photo by Shaun Lombard
Zoanthids Troubleshooting Q&A.
Having trouble with your Zoanthids? Here’s some the most common troubleshooting questions and answers.
Why aren’t my Zoas opening?
Struggling with shy Zoanthids? Don’t worry, it’s a relatively easy fix. First, wait a few days up to three weeks after relocating Zoas into your aquarium. Moving is stressful. These little fellas need to adjust to their new home before they feel comfortable enough to open.
If the Zoas aren't’ new and were previously wide open, then you likely have a water parameter imbalance or someone bothering them, like a hermit crab looking for food or a cleaner shrimp. Check pH and salinity levels with a good refractometer like Milwaukee first. More than likely, you’re tank’s suffering from salinity level fluctuations. Get this under control and Zoas will return to their previous, opened self.
Ummm…Help! My Zoas are melting! What do I do?
Like a scene out of The Wizard of Oz, if any of the few required parameters for Zoanthid health compromise, these brilliant creatures melt like the figurines in the cult classic, House of Wax.
Check the following to determine its cause:
- Light Exposure - Too much light exposure may cause melting. (Best way is to use a PAR Meter)
- High Flow - Too high or too low flow can result in this unsavory symptom.
- Water Parameters - Confirm you major water parameters (temperature, salinity, pH, alkalinity) are balanced and accurate.
What’s the black/brown string coming out of the Zoas mouth?
My dearest reefer, it’s poop! Black/brown strings are a good sign that your Zoanthids are eating and healthy.
Where’s my Zoanthids going? They seem to be disappearing!
The most common cause for a sudden disappearance isn’t a disastrous tank crash or parameter imbalance. The likely culprit is another tank inhabitant snacking on these beautiful corals. Review your tank residents and see if any of them have a penchant for Zoanthids. I definitely recommend doing this before adding Zoas.
I think my Zoanthids are sick. They’re covered in tiny growths!
Have you noticed small growths popping up along the sides of your precious Zoanthids? This is more than likely a symptom of Zoanthid Pox. Affected corals may be limited to a few or widespread throughout the entire colony.
Symptoms include tiny growths, which cause polyps to stay closed. If you think your Zoas have come down with the pox, it’s best to start treating them as quickly as possible. Do some research, but many reefers find success using an antibacterial-based treatment.
Will Zoanthids kill SPS corals or other Zoas?
Without going into too much detail, no. Zoanthids are peaceful and relatively harmless to surrounding SPS corals and with fellow Zoas.
Where do you buy Zoanthids?
This isn’t necessarily a troubleshooting hack, unless you can’t find a reputable supplier. Because of their popularity, finding a solid supplier shouldn’t be very difficult. I’ve had tons of success at my local fish store, but in case that’s not an option, here’s a few places I like shopping for zoas:
How do you frag Zoanthids?
Interested in fragging Zoas? While this adds a fun level of interaction with your aquarium, there’s several tips you must follow to ensure safety and success.
- Always wear protective gear to prevent poisoning yourself. Durable gloves, eyewear and face masks are recommended.
- If you’re serious about fragging Zoanthids, then you should invest in a diamond blade saw. Not sure where to start this hunt? Take a moment to read our Inland DB 100 Diamond Blade Band Saw Review for tips and ideas about this beneficial piece of equipment.
- If you need to frag them without damaging the rocks, use a precision knife and gently cut them from the rocks. It’s easy to do if you choose the right tool. I’m using the X-Acto Z Series #1 Precision Knife and I love it.
- I don't recommend fragging colonies with less than 12 polyps.
- Fragging Zoanthids is relatively similar to any other type of coral. Make sure you use the proper tools and the Zoas are healthy enough to be fragged. When successful, the frag will grow new polyps and tissue. At this point, you’re ready to sell, share or trade!
What Zoanthid types are your favorite?
I get asked this quite often. Choosing my absolute favorite Zoanthid type is impossible. However, choosing my favorite 15 Zoas is easy! Here’s a list of my most favorite 10 Zoanthids:
- ASD Hyper Jubilee
- Motley Crue Paly
- WWC Purple Monster Zoanthids
- LC Petroglyphs Zoas
- Rastas Zoas
- Utter Chaos
- WWC Space Juice Zoanthids
- LC Shadow Princes
- No, I just need to stop... there is a huge amount of amazing Zoas, it's impossible to answer this question!
Nature’s Brilliant Complexities - Zoanthid Final Thoughts.
The longer you swim in the sea of reef keeping, the more interesting species you’ll uncover. Whether you’re just starting out or desire a beautiful addition to your tank, Zoanthids are perfect for almost every reefer. From its stunning colors to its simple and straightforward care, I can’t recommend these interesting critters enough.
What’s your experience with Zoanthids? Do you have a favorite type that’s not listed?
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Happy Reefing!
by Yuliya Ivanov for ReefHacks.