Flatworm ID

[mac1284]

Hi everyone,

I’ve recently noticed something unusual in my aquarium. On the glass near the surface of the sand bed, I counted about 8 or 9 small flatworms. I’ve attached some images for reference.

What puzzles me is that I’ve never had corals or plants in the tank—just two clownfish and a healthy population of amphipods and copepods. This makes it odd that these flatworms have appeared.

Does anyone know what type of flatworms these might be? Are they potentially harmful to the tank or my clownfish? Any advice on how to deal with them would be greatly appreciated.

Thanks in advance for your help!

 

[Fish Styx]

Hi everyone,

I’ve recently noticed something unusual in my aquarium. On the glass near the surface of the sand bed, I counted about 8 or 9 small flatworms. I’ve attached some images for reference.

What puzzles me is that I’ve never had corals or plants in the tank—just two clownfish and a healthy population of amphipods and copepods. This makes it odd that these flatworms have appeared.

Does anyone know what type of flatworms these might be? Are they potentially harmful to the tank or my clownfish? Any advice on how to deal with them would be greatly appreciated.

Thanks in advance for your help!

That appears to be an Acoel flatworm. Harmless, really, but their populations can get out of control. Keep up with water changes and manage nutrients, and their numbers will thin out. You may also consider adding a natural predator, such as a wrasse.

There are number of products on the market to control / eradicate them, but I recommend not going this route. The only one I would use (and I do) is KZ flatworm stop, which has additional benefits for SPS; but that product requires continuous dosing and can be cost prohibitive for some.