The Five Worst Saltwater Aquarium Pests

This is a guest post by Nikki of Reef’d Up Aquatics.

These are arguably some of the most destructive and hardy saltwater aquarium pests.  Having to deal with some of these has been enough to make some reefkeepers get out of the hobby entirely.  I highly recommend the use of a good coral dip and quarantine procedure to prevent problems down the road.

1. Montipora-Eating Nudibranchs

These are probably the #1 Worst Saltwater Aquarium Pest for aquariums with Montipora coral as they reproduce tiny versions of adults that can immediately begin eating the coral, can hide in the smallest crevices, and are amazingly resilient to almost all treatments (including starvation!)  Currently, the best treatment is a potassium permanganate (a rather harmful chemical, so use caution) dip in conjunction with a separate treatment tank.  More info

Montipora-Eating Nudibranchs

Photo by Marc Levenson

2. Acropora-Eating Flatworms (Amakusaplana acroporae)

Acropora-eating flatworms are really nasty pests for aquariums with Acropora corals as they quickly reproduce, have excellent camouflage by using the coral’s own zooxanthallae, and no in-tank treatment method is yet proven 100% effective without significant losses.  The most common treatment methods are control through weekly removal through blasting them with a turkey baster, a weekly Fluke Tab treatment, or Levamisol (a pig de-wormer).  More info

Acropora-Eating Flatworm

3. Nuisance Anemones

Aiptasia and Majanos are able to clone themselves and overtake an aquarium very quickly.  Their powerful nematocysts (stinging cells) on their tentacles injure nearby corals and deter growth.  Control and eradication is done through natural predation (Berghia nudibranchs, butterflyfish, & peppermint shrimp) or chemical treatments (such as commercially available treatments like Joe’s Juice, kalkawasser paste, or even sodium hydroxide – also very harmful).  More info


4. Zoanthid-Eating Spiders

Unfortunately, even saltwater aquariums are subject to getting spiders.  Although these may cause nightmares, they are relatively easy to treat with manual removal (tweezers).  If the zoanthid colony can be removed from the aquarium, it can be treated with a good coral dip to help dislodge the spiders.

Zoa-eating Spider

5. Xanthid Crabs (Black-Tipped Claws)

Xanthid crabs have black-tipped claws and are often quite hairy (commonly referred to as Gorilla Crabs).  These are common hitchhikers on live rock, but rarely, if ever, reproduce in aquariums.  They are quite destructive to corals, other invertebrates, and sometimes even fish.  They are also difficult to catch (soda bottle traps sometimes work, but many aquarists resort to homemade spears).

Xanthid crab

In conclusion, these are only a few of some really bad saltwater aquarium pests.  A good quarantine procedure will help prevent almost all infestations.  If a quarantine system is not available, a good coral dip is a must.

Do you know of a saltwater pest that should have been included? Let me know in the comments below.

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