Why Is My Anemone Closed Up? [3 Valid Reasons]

You suddenly notice your anemone is deflated for a whole day. You’re now panicking and thinking your beloved species is dead.

But it would be best if you were clear about the situation to 

Why is my anemone closed up?

Well, there can be various causes behind anemone closing up. Sometimes they are deflated because they are consuming food or just resting.

But some negative reasons are starvation, overeating, and incorrect watering practice. In that case, you have to rescue them from the undesirable situation.

Why Does Anemone Close Up?

Maintaining anemones in a nano tank becomes challenging sometimes. This is due to you not being fully experienced. 

You must maintain strict feeding guidelines to keep your tank inhabitants from starvation. Otherwise, you’ll ruin your most cherished aquarium with dying green star polyps or shrunk anemones.

Anemone is sensitive about their eating habits. Deflated conditions can occur due to starvation. Improper lighting, water flow, and oxygen levels required for anemones can be blamed too. 

When your anemone shrinks, initially perceive that any of these reasons are causing it.

3 Reasons Behind Shrinked or Closed-Up Anemone

Now, let’s concentrate on the reasons that are causing deflated anemones. We have researched and collected 3 firm causes behind this issue. 

Here we’ve discussed each issue thoroughly:

Reason 1: Feeding Issue

Sometimes, you will notice your anemone abruptly has shrunk itself. Three food-based reasons can deflate it. 

These are hunger, overeating, or just the consuming process. Let’s get to know these facts in detail-

Fact 1: Consuming Food

It is one of the very common issues for the specimen. Anemone uses their tentacles to drag food to their mouths and deflate accordingly. This is a normal phenomenon for anemones.

They safeguard themselves from predators in the deep sea in congested water tanks. So, don’t worry about their health if this is the initial situation.

Fact 2: Overstuffed

Overeating is another cause for them to close up. Anemones curtail themselves so that no extra food gets in.

If you notice they are shrinking regularly, understand the imbalance of food supply behind it.


Overstuffing won’t kill them but you’ll waste a large amount of food. So, try to learn their food habits and act appropriately.

Fact 3: Malnourishment

Eventually, if you observe anemones losing their health and shrinking, it is malnutrition. Starvation is dangerous for them.

Sometimes fast water flow absorbs the nutrition and food before the species starts eating.

Also, bigger fishes can grasp all the foods served by other species. Sometimes, zoas won’t open up for this very reason.


To save them from this situation, keep a container over the anemones. Then apply a turkey baster to get food to your sea anemone.

Reason 2: Water Parameter

As we mentioned above, the wrong water flow can cause deflation too.

Sometimes the water parameter goes off and prevents nutrition from reaching the plants. In this case, anemones will close up themselves.


Don’t panic! We have the solution. If this caused your anemone to close up, go through a nutrition check of your water tank.

Check nutrition levels of calcium, magnesium, salinity, and other nutrients. 

Now, you must remember water parameters are important for every tank environment.

So, if the levels aren’t proper, you must take quick action. Change 20%-25% of water to restore the nutrient levels to normal. 

Then the water parameter will be regained. As a result, your anemones will get to their previous condition. 

Reason 3: Excessive Lighting

It is quite natural for anemones to close up during night hours. They do that to conserve energy or instinctively hide from potential predators.

You don’t need to worry about it unless they don’t open up the next day. 

However, they also close up themselves due to excessive lighting. If the lighting is too high for them, they will just shift the space accordingly. 


There’s no solution to this problem. But you should learn the light set up for their territory. 

Usually, anemones prefer low-level LED strips.

You can also upgrade your oceanic bio cube 14. It will enhance the outlook and create a healthy light setup for anemones.

How to Tell If Anemone Is Already Dead?

After treating your anemone, it might still be deflated. This is bad news for you. How so?

Well, there is a chance that probably your anemone has already died. From our assessment, there could be a few causes behind its death. These are discussed in short-

There’s a possibility that your tank wasn’t mature enough to raise a safe territory for the anemone. This often happens when someone impulsively tries to build an aquarium.

Then end up creating a life or death situation for plain corals or bubble-tip anemones.

Or, the anemone might be under stress due to the reasons above. However, sometimes there’s just no solid reason behind this undesirable death.


Question: Is it normal for anemones to close up at night?

Answer: Yes, it is normal for anemones to deflate at night. BTA (bubble-tip anemone) generally closes up at night.

White-tipped anemones usually shrink around one hour later. Lastly, GBTA will wait until midnight.

Question: How often should I feed my anemone?

Answer: The time will vary from one to another. A medium-sized anemone requires food once or twice a week.

Whereas you need to feed the larger ones frequently. But don’t forget to thaw frozen food before feeding.

Question: How to identify a healthy anemone?

Answer: Firstly, supervise your anemone firmly attached to the substrate and properly extended.

Then have an eye on their mouth. You will notice a deflated mouth that’s nearly puckered. If you see this, the specimen is healthy. 


That’s all about why my anemone is closed up. Hopefully, you’ve got all your answers by now.

So, find out the issue and take the necessary steps accordingly.

Until next time, take care!