Will Hermit Crabs Eat Zoanthids?

Last Updated on December 18, 2021 by cmoarz

You may have noticed your newly placed or establish Zoas seem to have disappeared seemingly overnight. Or worse, They seem to be shrinking and missing polyps every day. What gives? Obviously, you suspect your Hermit crabs are to blame. So will hermit crabs eat zoanthids?

Most hermit crabs (with a few exceptions such as large hairy hermits) won’t hurt your zoanthids, At least not on purpose.

The most likely explanation is the zoa melted away because they were already sick. This happens frequently when purchasing such delicate corals, especially from inexperienced local fish stores that buy them from sketchy breeders.

On the other hand, Sometimes hermit crabs will damage the polyps while attempting to get algae off of them. So while not trying to damage them on purpose, sometimes it does happen.

And, On occasion, You will have the odd hermit crab that will purposefully pluck at the polyps for seemingly no reason. It’s best to remove these crabs and place them away from the delicate corals. I’ve heard reported that Zebra Hermits and Emerald Crabs are the main culprits in this regard.

You should also be sure you don’t have any issues with water parameters or any other fish in the aquarium that might think these zoanthids would make a nice little snack.

The main reason we have hermit crabs in our coral tanks, to begin with, is that they act as part of our very important cleanup crew. Without them, chaos could ensue!

The truth is, If you see your hermit crab attacking your polyps, it’s probably just doing its job. That Polyp is dying and the hermit is helping the system by cleaning it up which is exactly what you want it to do.

Can Hermit Crabs Kill Corals?

If a hermit crab kills a coral you can be 99% sure it was accidental. Usually, while they are trying to pull bubble algae or the likes off the coral but accidentally damaging the corals in the process.

Zoanthids can be easily killed by other means such as chemicals, heat, and especially stings from other corals such as frogspawn.

If you suspect your hermit crabs are responsible for the damage to your zoas, the best thing to do is remove them and place them in a separate tank where they can do no further harm, or isolate them in the same tank but so they can’t get to the corals.

You can also make sure to feed them well so they aren’t as interested in scavenging the hard-to-reach algae off the delicate corals.

Do Emerald Crabs Eat Zoanthids?

As opportunistic feeders, emerald crabs will sometimes go after Zoanthid polyps. Which is a good reason to keep them in a separate tank or placed into the sump.

But for the most part, they won’t eat them purposefully (unless they really want to!), although they can and will damage them and push them around at times. They will also make a nice snack of hammers, and frogspawn coral.

The best way to avoid this damage is to just move the frag away from where the crabs can’t get to them easily or move them into the sump.

Do Blue Leg Hermit Crabs Eat Coral?

Blye leg hermit crabs won’t eat healthy coral but their pointy legs can damage them while they scavenge for food.

If the coral isn’t healthy or it’s dying, it’s entirely possible the hermits will eat it.

But if the coral is healthy and looks like it should, then your blue leg hermit crabs won’t touch it. Or at least, not on purpose!


Owner of AquariumGravel.com and also owner of actual Aquarium Gravel believe it or not! ;). Setting up beautiful aquarium sceneries and habitats since I was very young. Enjoy!