Why Is My Acan Coral Not Puffing Up?

This post may contain affiliate links. As an amazon associate I earn from qualifying purchase. Learn more

You’ve probably bought an acan coral, and you wonder why your acan coral is not puffing up as it used to in the store.

Or maybe you already have an acan that used to be all puffed up but suddenly deflated without any warnings.

If any of these situations have happened to you, don’t worry, because, in this article, we will discuss all the reasons that may cause acan corals to deflate. In addition, we will mention several tips on how to get back your acan to its former glory days.

The most common reasons why acan corals are not puffing up are inadequate flow, improper lighting, and lack of nutrients in the reef tank.

That was the short version! Now let’s deep dive and explain everything in more detail.

Let’s get started!

Acan Coral Not Puffing Up



Acan corals prefer low light, and if you place them under high-intensity lighting, there is a big chance they won’t open. 

Most people keep their acan corals on their sandbeds. Some hobbyists keep them in shaded areas of their tanks.

If you want to place your acan coral on a more visibly or higher spot in your tank, then do it gradually. However, I recommend keeping it in the lower areas in your tank for better chances of success and more puffiness.

Water flow

When it comes to water flow, acans prefer low to moderate. If your acan coral is not puffed up, there’s a chance of too much flow in your reef tank or too much flow directly hitting your acan.

Try to lower the flow and see if your acan coral is starting to puff up. But be careful because too little flow can also be inadequate for your acans. 

Too little flow, and your polyps will get covered in detritus. 

With too much flow, the polyps will get retracted. Find the sweet spot in your reef tank, and your acan coral will start puffing up.


Acan corals get their nutrients through photosynthesis, but they benefit from additional feeding. When I feed my LPS corals, they are all puffed up the next day.

If you are running a low nutrient system, that might be the problem. Target feed your acan corals a couple of times a week, and trust me; you will see a big difference.

Water parameters

I assume that you regularly test your water parameters in your reef tank. 

We can only guess what caused your acan coral to deflate without testing. 

I highly recommend weekly testing, especially when you keep LPS coral which can be affected by alkalinity swings. 

If the water parameters are on point, there is probably another reason why your acan is not puffing up.


If you’ve just bought your acan coral and it’s not looking healthy, it’s probably because of the stress caused by changing the environment.

Give it time for your coral to acclimate to the conditions in your reef tank. 

Sometimes corals look unhappy for weeks and then look better than ever out of nowhere. It might be the case with your acan coral.

Types of Acan

Some types of acan corals look puffier than others, and it’s nothing to do with all the reasons mentioned above. 

For example, the Acan Lord will have a puffier look than the Acan Echinata.

Final Thoughts

I hope this article was helpful and that you learned something new about these corals.

Acan corals are one of the most popular corals in the saltwater aquarium hobby. And why they wouldn’t be. 

There are relatively easy to keep, they come in different varieties and have nice color patterns. 

Leave a Comment