Why Is My Anemone Shrinking?- 3 Reasons & Solutions

We, hobbyists, know how much we love our aquarium fishes and plants. However, most of us are unaware of the problems that our aquatic items face.

So, if you see your anemone shrinking, it can be a reason for concern. 

Why is my anemone shrinking

The main reason for anemone shrinking is starvation. Stress can also be one of the core reasons for your anemone shrinking.

But in this case, it’ll quickly turn back to its old self if treated properly. Poor lighting can also be the reason for your anemone shrinking.

But anemones also sometimes shrink naturally. That is when they eat or excrete waste.

Still confused? Don’t worry; we figured this might happen. That’s why we’ve discussed everything in detail. 

Spare a few minutes and have a read.   

Why Is Your Anemone Shrinking?

Most aquarium hobbyists often find several problems regarding corals, anemones, and fish. For example, Duncan corals may not always open when you keep them. 

These kinds of problems need direct answers. If you don’t know what the actual problem is, it’s hard to solve it. 

It is common for anemones to shrink at night. In the ocean, anemones shrink up to 20-25% at night. So, lighting can be an issue. We’ll elaborate on this later. 

Your anemone will also shrink when it’s eating or excreting waste. It’s perfectly normal, and there’s no reason to worry about it. 

Besides that, your anemone doesn’t have a reason to shrink. It should be taken seriously because it’s certainly not a good sign. 

Here, we’ve listed some reasons and provided solutions for you. Go through the topics individually, and you may find the solution. 

Reason 1: Continuous Starvation Aren’t Good For Anemone 

Anemones shrink for a variety of causes, one of which is famine. Your anemone is shrinking but not due to deflation. If that’s the case, malnutrition is among the most likely causes. 

Now, there are symptoms of this. These are- slightly shorter tentacles, color fading, and a diminishing diameter. 

Solution: Maintain Proper Nutrition

It’s important to know anemones do not need food every day.  Feed your anemones once a week or more frequently to help them develop faster.

Protein-rich diets are the best foods for anemones. Scallops, clams, shrimp, and mussels are all great foods.

Always remember, keeping an anemone is not easy. You’ll need to do your research before committing. We suggest you start by making your fish tank perfect for anemones

Reason 2: Excessive Stress May Cause Shrinkage

Anemones can shrink themselves if they’re feeling stressed. If this happens, it’s better to observe your anemone for a while. 

If you notice them shrink further, you’ll have to find the reasons immediately. 

Solution: Create The Right Environment

The saltwater aquarium’s environment must be carefully maintained. Try to maintain a temperature range of 75.2 to 82.4 Fahrenheit. 

The salinity should be in the range of 1.020 to 1.026 sg. You’ll need a powerful filtering system. 

Daily, you should measure the temperature, water quality, salinity, and pH. For aquarium care, change 15 to 30 percent of the water every three to four weeks.

However, it’s not something to worry about if it happens occasionally.

Furthermore, anemones often split if they’re under stress. If that occurs, just do the steps we’ve mentioned above. 

Reason 3: Poor Lighting Can Make Anemone Shrink Faster 

Proper lighting is essential for anemones. If they don’t get enough lighting, they will die of malnutrition. 

But first, you’ll see them close up or shrink for an extended amount of time. So, when this happens, it indicates that you need to change the lighting. 

Solution: Maintain A Proper Lighting System

Sea anemones demand a lot of light. Shrinking is usually health-related, so lights play an important role here.  

The recommended PAR ratings for anemones are between 220 to 370 PAR. You’ll need specific T5 bulbs, LED lights, or metal halide bulbs.

You may also consider upgrading your oceanic biocube 14 lights now. This way, you’ll have a reliable lighting system.



Question: What’s the deal with my anemone’s deflated appearance?

Answer: It’s because they remove stale water from their bodies regularly. For a day or two, these anemones should begin to expand once more.

A deflated anemone may also indicate death if it has been more than two days. 

Question: How can I tell whether my anemone is in good health?

Answer: Healthy anemones will always stay attached to the surface. Check if they’re attached or not. If your anemone is detached, check the water parameters. 

Question: What is the reason for my anemone shrinking at night?

Answer: Deflation is typical in sea anemones, particularly at night.

However, there’s a distinction to be made between deflation and shrinkage. If your sea anemone is becoming noticeably smaller, this indicates malnutrition. 


That was everything on why is my anemone shrinking. By now you should have a pretty good idea about this topic. 

Here are some parting words from us. You can feed silversides or shrimps to anemones. They can keep your anemones healthy and lively.