The crabs I will be considering include the true crabs (Brachyura) and some "crabs" from Anomura, including hermit crabs (Paguroidea) and porcelain crabs (Porcellanidae). Horseshoe crabs (Limulidae) will be excluded.
Over the years, I have heard mixed reports on how "reef-safe" crabs are in the hobby, especially since many are opportunistic feeders, can walk over corals, and require snail shells (for hermit crabs), but there are a few that I have never heard any bad incidents from/seem to be widely considered to be safe in reef tanks. Here, I have compiled the "reef-safe" crabs I can recall. Does this list seem reasonable? Should more be added or are there no crabs that can truly be considered "reef-safe?" Please do share your experiences/thoughts.
Note: these are not crabs which I have kept (an emerald crab (Mithraculus sculptus) in an old tank that I never really paid attention to and zebra hermit crabs (Calcinus laevimanus) that seem to be aggressive to one another in the absence of established, algae-covered shells), so take the information I have provided with a grain of salt.
No incidents:
Porcelain crabs (Porcellanidae), filter feeders, the claws are not used to catch food, 1":
Guard crabs (Trapezia sp.), helps keep some SPS corals clean of mucus and detritus and wards off predators, 1":
Somewhat suspicious:
Pom pom crabs (Lybia sp.), carries anemones to deter predators and collect food, anemones may cause minimal damage to other corals that doesn't seem to be an issue, 1":
Micro decorator/mime crab (Acanthonyx, Epialtoides, and Epialtus sp.), I have heard these might wear small coral, but it doesn't seem to be an issue (maybe with a small frag though), 1":
Over the years, I have heard mixed reports on how "reef-safe" crabs are in the hobby, especially since many are opportunistic feeders, can walk over corals, and require snail shells (for hermit crabs), but there are a few that I have never heard any bad incidents from/seem to be widely considered to be safe in reef tanks. Here, I have compiled the "reef-safe" crabs I can recall. Does this list seem reasonable? Should more be added or are there no crabs that can truly be considered "reef-safe?" Please do share your experiences/thoughts.
Note: these are not crabs which I have kept (an emerald crab (Mithraculus sculptus) in an old tank that I never really paid attention to and zebra hermit crabs (Calcinus laevimanus) that seem to be aggressive to one another in the absence of established, algae-covered shells), so take the information I have provided with a grain of salt.
No incidents:
Porcelain crabs (Porcellanidae), filter feeders, the claws are not used to catch food, 1":
Guard crabs (Trapezia sp.), helps keep some SPS corals clean of mucus and detritus and wards off predators, 1":
Somewhat suspicious:
Pom pom crabs (Lybia sp.), carries anemones to deter predators and collect food, anemones may cause minimal damage to other corals that doesn't seem to be an issue, 1":
Micro decorator/mime crab (Acanthonyx, Epialtoides, and Epialtus sp.), I have heard these might wear small coral, but it doesn't seem to be an issue (maybe with a small frag though), 1":
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