Neopetrolisthes ohshimal
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| Difficulty | Low |
| Minimum Tank Size | None |
| Diet | Carnivore |
| Water Parameters | 72-78 F, pH 8-8.4, Salinity 1.020-1.025 |
| Aggression | Peaceful |
| Size | 1" |
The Porcelain Anemone Crab is one of my favorite crabs. They only show aggression when defending their territory, and even then they are unlikely to harm anything. They often make their nests around anemones or corals, but are fairly easily chased away.
The Porcelain Anemone Crab will not attack fish or inverts. Any invading species will often drive them away, meaning this crab functions much more as prey than predator.
What really sets these crabs apart from the rest is their smaller, feeding arms. They hold large, net like appendages out to filter feed. Seeing this in action is amazing and something no other crab can do.
Note: This article is about the Porcelain Anemone Crab, not to be confused with the Porcelain Crab. These guys are not similar and should not have their info used as a basis for the other.
Behavior & Aggression
These crabs will normally behave just as any other crab would. They frequently crawl around on rocks and corals, picking at them and eating whatever they find. The main difference is their peaceful nature.
When their are a pair of these crabs they can often be seen defending their homes, however they will still run if any real threat becomes apparent. Never the less the display is always amusing to watch.
When disturbed the Porcelain Anemone Crab will often wave his arms at the aggressor, hoping to scare them off. If this fails the crab will begin a full retreat, ducking into cover in either rockwork or anemones. This makes the Porcelain Anemone Crab fantastic for those who want crabs but also want fish commonly harassed by crabs.
This same behavior goes for most inverts, however some will run from this crab. Typically any and all shrimp will flee from a crab, however my Coral Banded Shrimp did get into a hand holding contest (his claw holding the porcelain’s) with this crab before. After a short while the shrimp let go and darted backwards, away from the crab.
This is why the anemones do not sting the crab. The crab is allowed to clean the anemone and in exchange will chase away any would be food thieves. Shrimp are one of the quickest and most common thieves corals and anemones fear.
The one note of aggression these crabs have is towards one another. Unless you have a mated pair or a large tank with multiple anemones you should not keep more than one of these crabs. The will fight one another, taking legs and arms until one flees from the other.
Diet & Feeding
Feeding this crab is not too difficult, as they are filter feeders whom will eat whatever is in the water. The main issue here is when kept in a nano tank. These smaller tanks often cannot keep the crabs and their anemones alive, meaning other food sources are required. Large tanks with more food being uneaten by the fish are prime candidates for the Porcelain Anemone Crab.
These crabs will readily accept flakes and pellets, however they will not go far in search of them. This means you will need a method for spot feeding the crabs in smaller tanks. I typically use a pair of tweezers. It’s always fun to feel the crab yank the food right out of them.
Is there a reason a porcelain crab would leave a rock anemone even if it wasn’t chased away? My had been hosting for 2 months then one day he left and hasn’t returned,
Hey Kristen.
It could be that your crab ran around the tank one day and found he gets much better results filter feeding somewhere else in the tank. I had one of these crabs make a cross tank trip when I lowered the flow in one of my smaller tanks. He hangs like a bat under one of my rocks now instead of sitting on at the top of the tank.
Additionally these crabs are not great at defending themselves. They will try and scare away harassers, but if you have a fish that is too tough for them they may go into hiding.