Reef Aquarium Pests And How To Eradicate Them

Have you ever encountered any unwelcome guests inside your reef aquarium? 

Aquarium pests are tiny critters that aquarists will experience at some time in their hobbyist journey, so it is essential you know what to look out for and what to do if they are causing a nuisance. 

In this article, we will cover 8 common saltwater aquarium pests and how to remove them. 

Where Do Pests Come From?

While it may seem that your aquarium pests have appeared out of nowhere, they don’t just magically appear, so they must have come from somewhere. 

Pests typically hitchhike into reef aquariums via aquatic plants, live rocks, decor, or even fish or corals that have come from an infected tank. 

8 Common Aquarium Pests

Once pests enter your aquarium, under the right conditions they can rapidly reproduce, therefore, you need to be able to identify them to eradicate them.

There are eight common aquarium pests found in reef tanks you should be aware of. 

#1: Aiptasia Anemone

Probably the worst of them all is aiptasia. Aiptasia anemones are expert hitchhikers, making them the most common aquarium pest in reef aquariums. 

Their favorite mode of transport is live rock, but they can also enter your aquarium on a new coral frag. 

Once aiptasia enter your aquarium, they spread like wildfire, and will quickly dominate your aquascape. This is bad news for your tank inhabitants, as they punch a powerful sting, that can harm or even kill your corals.

How To Remove Them?

• Chemical Treatments: Inject the aiptasia anemone with a hypodermic needle containing a thick alkaline paste, such as Frank’s F- aiptasia fix. This works, but it requires repeat applications to fully eradicate them. 
• Natural Predators: Berghia Nudibranchs and Aiptasia-Eating Filefish are your best bet, as they love munching on aiptasia. Peppermint Shrimp and Copperband Butterflyfish are also known to eat aiptasia, but note that sometimes they don’t. 

#2: Coral-Eating Nudibranchs

There are different coral eating nudibranchs, but the most common are monti-eating nudibranchs and zoanthid-eating nudibranchs. 

They are fairly difficult to identify as they are aquarium magicians! Coral-eating nudibranchs take on the color of the prey as they munch their way around your corals. The best chance of spotting them is during the night, when they are most active. 

Another thing to look out for is any tiny bite marks on your coral’s tissues where the nudibranchs have eaten the flesh. 

How To Remove Them?

• Coral Dips: Dips work wonders killing adult nudibranchs, but the eggs will often survive the treatment. 
• Physical Removal: For egg clusters, physical removal by carefully cutting them off the rock is the best option. Adults can also be removed one by one, using forceps. 

#3: Acropora-Eating Flatworms (AEFW)

Flatworms are also one of the most dreaded coral predators. They start from the bottom of your coral and work their way up. Like nudibranchs, these flatworms also take on the color of the coral they consume, making them difficult to identify. 

Once they enter your aquarium, the flatworms will damage and irritate your coral before you spot these pests. 

How To Remove Them?

• Coral Dip: Dips work well on adult flatworms, less effective on eggs. Coral dips should be repeated over 5-6 weeks. 
• Cutting The Frag: Sometimes cutting the eggs off the coral is the best choice. 
• Natural Predators: Wrasses like Melanarus and Radiant Wrasses are known to eat flatworms. 

#4: Planaria

Planaria, more commonly known as Red or Brown Flatworms, may not prey on your coral’s flesh, but they are still a problem for your aquarium. 

They are most common in aquariums that have excess detritus and when aquarium maintenance is neglected. 

Planaria rapidly reproduce in aquariums, quickly covering your corals and rocks. As the worms smother your corals, they can restrict light, which is essential for your coral to survive. 

If infections carry on, your corals will eventually die from a lack of light or increased stress. 

How To Remove Them?

• Physical & Chemical Removal: Physically removing along with reef-safe treatment such as Flatworm eXit or Flatworm RX is the best removal process. 
• Natural Predators: Some Wrasse and Dragonets will eat planaria. 

Note: When planaria die, they release a toxin into the water. So, it is critical that you siphon as many planaria out of the aquarium before and after chemical treatment is applied. 

#5: Red Bugs

Red bugs are tiny crustaceans, known for targeting SPS corals, specifically Acropora corals. Once infected, your coral will become irritated, and eventually, it will stop extending its polyps. 

No larger than a pen tip, red bugs are very tough to spot inside your reef aquarium. Unfortunately, you are more likely to see coral damage before you see them. Only if you take a close look at your infected corals, will you notice the teeny tiny red dots.

How To Remove Them?

• Coral Dip: Proper dipping will help remove the red bug infestation. If the treatment from your local fish store doesn’t work, then you can ask a veterinarian for a stronger medication. 

When treating corals with a coral dip, check the ingredients, as many medications such as Interceptor are toxic to crabs, snails, and shrimp. 

#6: Bristle Worms

Bristle worms are less of a threat, and more of a nuisance, if they enter your reef aquarium. They feed and remove detritus and decaying organic material inside the aquarium. This is why they are often referred to as beneficial hitchhikers. 

Usually, 99% of the time bristle worms are not threatening, but they are very unsightly and will devour corals or fish if they start to perish. 

How To Remove Them?

• Physical Removal: Using forceps and gloves, you can easily remove them, if you can catch them. Wait until the lights go out, as this is when they leave their burrows to scavenge the aquarium. Forceps and gloves are necessary as the worms have bristles that can go into your skin and cause irritation. 
• Reduce Detritus & Waste: If population increases are the issue, focus on filtration and reduce the amount of detritus and waste inside your aquarium.

#7: Majano Anemone

Majano anemones are similar to aiptasia in that they can quickly take over your aquarium, smothering your corals. Majano anemones can also sting and irritate your corals to the point of death. 

How To Remove Them?

• Chemical Treatment: Using a treatment like Frank's F-Aiptasia is the most effective way to eradicate them.
• Natural Predators: Bristle-Tail Filefish will eat smaller Majano anemones, however, they can be problematic in reef aquariums so keep a close eye on them with your other inhabitants. 

#8: Asterina Starfish

The least threatening from the list of reef aquarium pests, yet very common, are asterina starfish. These starfish are usually no cause for concern unless your corals have any dead or decaying flesh. 

Many hobbyists are not too worried about them unless they start to rapidly reproduce and take over the aquarium. 

How To Remove Them?

• Physical Removal: Asterina starfish can easily be plucked out of the aquarium with tweezers or forceps. 
• Natural Predators: Harlequin Shrimp are perfect voracious predators and will happily consume asterina starfish, plus they look fantastic in reef aquariums!

Summary

Aquarium pests typically are a nuisance, but some can also be harmful to your aquarium community. The worst of the bunch are aiptasia anemones and coral-eating nudibranchs. The good news is, most aquarium pests are simple to eradicate with a coral dip, physical removal, or by the introduction of natural predators. 

If you need advice on pest control, or you need help with your aquarium set-up or reefing supplies, do not hesitate to contact the Reefco team!