Zoanthids Not Opening? – Let’s Discover the Reason Why!

If you are new to caring for zoanthids corals, you should have a thorough understanding of why your zoanthids are not opening. We might have precisely the item to clarify things for you!

Why are your zoanthids not opening?

Zoanthids are three forms of coral that have similar development, look, and properties. They are zoanthids, palythoa, and protopalythoa.

Zoanthids are colonial soft corals that may be found on tropics and subtropics beaches. Zoanthids are photosynthesis, which means they have symbiosis zooxanthelitic algal that generates a large portion of their sustenance.

That’s just a whiff of what’s to come. Let’s take a closer look at it.

Why Are Zoanthids Not Opening?

There are some possibilities as to why your Zoanthids aren’t opening. A common reason for this is that some insects, such as cleaner shrimps move on them. That does not sit well with the Zoanthids.

Many insects are frequently seen crawling or sprinting over a Zoanthids colony. It will force the corals to close, and it may take time for them to reopen. But it usually does not always take much time.

However, a fish is likely eating at the Zoanthids, making it uncomfortable and preventing it from reopening. 

I used to have a red aquarium disturbing my Zoanthids colony enough that I relocated it to another one. This is not a typical occurrence, but that does occur now and then.

Your water conditions might also be the cause of your Zoanthids not opening. If your saline fluctuates or if some other condition, like PH, is amiss, they may remain locked up. 

The Zoanthids would reopen well when you check your water temperature and fix anything out of range.

When your Zoanthids are fresh in your aquarium, it may take a little time for them to adjust and feel at ease in their new surroundings.

How Long Does it Take for Fresh Zoanthids to Open?

When you add fresh Zoanthids to your reef aquarium, they will take some time to open. It can happen quickly at times and sometimes take days to weeks. 

Regularly acclimatize new corals to the aquarium to help them adjust to new surroundings and circumstances.

Water Conditions for Zoanthids

Zoanthids are robust corals that can live in less-than-ideal conditions. However, you should constantly verify that your water parameters are within the right range.

It will guarantee that the coral remains healthy and develops properly.

For zoanthids, it is critical to keep the temperature of the water steady. They don’t like changes. Regulate the temperature to 78 degrees Fahrenheit. 

The PH should be 8.0-8.4, and the saline should be 1.025. Further water factors to examine include potassium, calcium, and alkali.

How to Tell if Zoanthids are Dying

When your Zoanthids aren’t trying to open up for lengthy periods, are changing color, and appear to be fading away, it might be an indication that the corals are dying.

Zoanthids, on the other hand, are rather resilient, so don’t abandon them. 

Here are some things to keep an eye out for:

  • Zoanthids Polyp will look to be withering and collapsing.
  • The polyp is disintegrating and may tear apart.
  • Awful stink and a lack of body.
  • Color and pigmentation are dark.

Health Benefits of Zoanthids

It’s essential to follow basic health advice to keep your Zoanthids from not opening correctly.


Zoanthids will get from feedings regularly. Target feeding is a fantastic idea that can be done several times weekly. 

Certain meals, including brine shrimp, plankton, krill, and copepods, will appeal to them.

Zoanthids can collect food from the deep ocean because if you don’t want to target feed, do it with a coral meal that you can dissolve in water and put into a large flow section of the aquarium.

It is not required to feed zoanthids as they have a photosynthetic relationship with zooxanthellae, but it will help them improve, keep coloration, and remain healthy.


Zoanthids can tolerate a wide range of illumination conditions. They enjoy medium to high illumination since it allows their polyps to develop and exhibit more colors. 

However, be sure that the light is not too bright since this might end up losing color quickly.

For your Zoanthids, use a high-quality reef light source, T5, or metal halide. Blue ultraviolet light LEDs or bulbs provide some of the greatest colorations in Zoanthids. It truly brings out the colors in the aquarium.

Water flow

Zoanthids require a low to moderate flow with a diverse pattern. If the water flow becomes too high, they may have difficulty releasing their polyps, which will have major consequences for the coral’s health. 

For Zoanthids, a lesser stream is preferable over a high flow. You’ll know it was the proper flow for them when you see the coral polyps expanding and their colors truly displaying.

They will notify you if somehow the flow is unacceptable to them.


Question: Do zoanthids like dirty water?

Answer: That zoanthids may survive in clean and unclean tanks as long as periodic nutrients are given is consistent with my observations.

Most zoanthids thrive in high-nutrient tanks, with or without supplemental feedings.

Question: Do zoanthids need phytoplankton? 

Answer: No, phosphorus spikes may occur as a result of adding fertilizers to the water. 

Question: Can you overfeed a coral? 

Answer: Overfeeding your corals will not harm them. They just consume what they require. On the other side, adding too many organics to your tank by overfeeding might harm it.


We’ll be saying our goodbyes to this. I hope you now understand why your zoanthids not opening. You can email us if you have any more questions or need assistance.