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13 Reasons Your Zoanthids Are Dying!

The popularity of coral keeping just keeps on increasing as more and more people look to add corals to their marine tank or try to setup a dedicated reef tank.

Then we have zoanthids, one of the most popular beginner friendly corals in the hobby so with there being an absolute ton of beginner coral keepers out there starting out with zoanthids, it’s easy to see why we see so many people asking about their zonathids dying.

We have already published our article going over zoanthids melting as well as one article on zoanthids not opening.

For todays article, we will be going over the most common reasons that your zoanthids may be dying to try and help as many of our readers as possible work out the problem with their corals as well as save them.

Why Your Zonathids Are Dying!

We have our list of the more common reasons that your zoanthids may be dying below and then under that, we will take a more detailed look at each potential problem:-

  • Low Quality Water!
  • Zoa Pox!
  • A Lack Of Nutrients And Food!
  • Unsuitable Water Flow!
  • Issues With Water Salinity!
  • Sudden Change In Water Parameters!
  • The Placement Of The Coral!
  • Unsuitable Light!
  • Non-Reef Safe Tank Mates!
  • Water pH Levels!
  • Low Calcium And Magnesium Levels!
  • Ammonia And Nitrate Levels!
  • Water Temperature!

Please note that two or more of these problems can sometimes be present in a tank at the same time. Many beginners overlook this and presume that their problem is with a single issue and focus on that single problem when in actual fact, there could be multiple problems with your tank.

Low Quality Water!

This has to be one of the main reasons that we see beginner coral keepers struggling with their tanks, they neglect to invest in a decent aquarium test kit and just presume that because the water looks ok, it must be ok.

If you are keeping corals, it’s so important that you have a good quality aquarium test kit as corals are very sensitive to water quality.

We would recommend that you invest in a good quality aquarium test kit like the Red Sea Reef Test Kit for accurate results.

If you are using tap water, its also important that you use a good quality water conditioner to remove any chlorine or chloramine from the water as this can be harmful to your corals.

Zoa Pox!

This is a virus that can affect zoanthids as well as other corals and it can be deadly if left untreated. Zoa pox usually looks like white spots on the coral tissue and it can quickly spread to other corals in the tank.

If you suspect that your zoanthids have zoa pox, the best course of action is to remove the affected coral from the tank and place it in quarantine.

We have a dedicated article going over treating zoa pox that should be able to help you if you think that this zoa pox is the reason that your zoanthids are dying.

A Lack Of Nutrients And Food!

Corals need a steady supply of nutrients and food to stay healthy and if they are not getting enough, they will slowly start to die. The main source of food for corals is plankton but in a home aquarium, this can be in short supply.

You can supplement your corals diet by feeding them small pieces of meaty foods like mysis shrimp or brine shrimp. We would recommend that you feed your corals 2-3 times per week.

Unsuitable Water Flow!

Zoanthids usually prefer a low to moderate water flow tank, ideally low water flow if possible but we have noticed some people having issues with their zoanthids dying due to accidentally putting them in a high water flow tank.

If you are only able to use a high water flow tank for your zoanthids then you can sometimes tweak the placement of your zoanthids in the tank to move them to an area with less water flow to help the zoanthids thrive.

Issues With Water Salinity!

One of the more common issues that we see with beginner coral keepers is that they do not have a good grasp on maintaining the correct water salinity in their tank.

Water salinity is measured in Specific Gravity (SG) and for reef tanks, the ideal SG is between 1.023 – 1.025. If your SG falls outside of this range, it can cause problems for your corals.

A good quality aquarium refractometer is the best way to measure the salinity in your tank and we would recommend that you invest in one if you are keeping corals.

Sudden Change In Water Parameters!

Zoanthids are very sensitive to changes in water parameters and a sudden change can sometimes be enough to kill them.

If you need to make a water change or add something to your tank, we would recommend that you do it slowly over a period of time so that your zoanthids can adjust to the new conditions.

A partial water change of between 10% and 20% is usually what we recommend to our readers as this usually allows you to change a decent amount of the water in your tank without changing the water parameters too much.

The Placement Of The Coral!

Zoanthids need to be placed in an area of the tank where they will get a good amount of light but not too much as this can bleached the coral.

We would also recommend that you place your zoanthids on a piece of live rock or rubble so that they have something to attach themselves to.

If you are using a powerhead for water flow in your tank, we would recommend that you position it so that the water flow is not directly hitting the zoanthids as this can stress them out.

Unsuitable Light!

Zoanthid need a good quality lighting system to stay healthy and if they are not getting enough light, they will slowly start to die.

The majority of zoanthids should be fine in a range of lighting conditions but if you do think that your zoanthid is dying then trying to maintain a moderate lighting intensity for your zoanthid is probably going to be the best option in most situations.

Keep in mind that many of the cheaper lighting units on the market for the aquarium keeping hobby are either inaccurate with their lighting output or inconsistent meaning that the problem may actually be the lighting unit that you are using on your tank rather than the actual settings that you have dialed in on your lighting unit.

Non-Reef Safe Tank Mates!

If you have zoanthids in your reef tank then it is very important that you do not have any non-reef safe fish or invertebrates in your tank as they can pose a serious threat to your zoanthids.

Some of the more common non-reef safe tank mates that we see people keeping with their zoanthids are damselfish, dottybacks, and clownfish.

While these fish may not seem like a big threat to your zoanthids, they can actually cause a lot of damage to them if they decide to pick on them by nipping them or eating them.

We would also recommend that you avoid keeping any fish that are known to eat or nip at zoanthids in your tank as this is a very common reason that zoanthids end up dying.

Water pH Levels!

The ideal pH level for a reef tank is between 8.2 and 8.4 but if your pH levels fall outside of this range, it can cause problems for your corals.

If you notice that your zoanthids are not doing well or they are dying, one of the first things that you should check is the pH level of your water.

If the pH level in your tank is too low, it can cause problems for your zoanthids and if it is too high, it can also cause problems.

We would recommend that you test the pH level in your tank with a good quality aquarium test kit and if it is not within the ideal range, we would recommend that you take steps to adjust it.

One of the best ways to adjust the pH level in your tank is to use a product called Seachem Reef Buffer which can be added to your tank to raise or lower the pH level as needed.

Low Calcium And Magnesium Levels!

If the calcium and magnesium levels in your reef tank are too low, it can cause problems for your zoanthids.

Calcium and magnesium are two of the most important elements in a reef tank and if they are not at proper levels, it can cause problems for your corals.

We would recommend that you test the calcium and magnesium levels in your tank with a good quality aquarium test kit and if they are not within the ideal range, we would recommend that you take steps to adjust them.

One of the best ways to adjust the calcium and magnesium levels in your reef tank is to use a product called Seachem Reef Complete which can be added to your tank to raise or lower the calcium and magnesium levels as needed.

Ammonia And Nitrate Levels!

If the ammonia and nitrate levels in your reef tank are too high, it can cause problems for your zoanthids.

Ammonia and nitrate are two of the most important elements in a reef tank and if they are not at proper levels, it can cause problems for your corals.

We would recommend that you test the ammonia and nitrate levels in your tank with a good quality aquarium test kit and if they are not within the ideal range, we would recommend that you take steps to adjust them.

One of the best ways to adjust the ammonia and nitrate levels in your reef tank is to use a product called Seachem Prime which can be added to your tank to remove ammonia and nitrate from the water.

Water Temperature!

The water temperature in your reef tank is very important and if it is not within the ideal range, it can cause problems for your zoanthids.

The ideal water temperature for a reef tank is between 76 and 78 degrees Fahrenheit but if the water temperature in your tank is too high or too low, it can cause problems for your corals.

If you notice that your zoanthids are not doing well or they are dying, one of the first things that you should check is the water temperature in your tank.

If the water temperature in your tank is too high, it can cause problems for your zoanthids and if it is too low, it can also cause problems.

We would recommend that you test the water temperature in your tank with a good quality aquarium thermometer and if it is not within the ideal range, we would recommend that you take steps to adjust it.

One of the best ways to adjust the water temperature in your reef tank is to use a product called an aquarium heater which can be added to your tank to raise or lower the water temperature as needed.