Hello everyone, i'm new here. My husband and I are just starting our first saltwater tank. We have extensive experience with freshwater but this is our first attempt at saltwater. We have purchased live rock and we obviously got a hitchhiker on it, a crab. I am not sure what type of crab this is or how large he will get, what he's supposed to eat, etc but I do know that he's feasting on our red algae that was present on the live rock. I find him rather cute but if he's going to get huge or cause lots of problems he will have to find a new home. Anyone know what he is?
What kind of crab am I?
- Thread starter Deb76
- Start date
Welcome to the site 
He looks like he might be a red mithrax crab, like the one shown here: Live Rock - Tampa Bay Saltwater Aquacultured Live Rock - The Package Organisms (under crustaceans, there are a few pics).
There are some more crab pics here: Crab Hitch Hikers
If it is a red mithrax, he will eat fish/snails, so it would be better to remove him.
He looks like he might be a red mithrax crab, like the one shown here: Live Rock - Tampa Bay Saltwater Aquacultured Live Rock - The Package Organisms (under crustaceans, there are a few pics).
There are some more crab pics here: Crab Hitch Hikers
If it is a red mithrax, he will eat fish/snails, so it would be better to remove him.
The Red mithrax is similar the the "emerald mithrax crab" and is generally a safe crab to have. They are opportunistic feeders and if they do not get enough food, can go after small fish, coral and inverts... I have personally kept the emerald crab without any issues, I just made sure to feed it some meety items once or twice a week.
I would personally leave it in the tank... but that is your choice!
I would personally leave it in the tank... but that is your choice!
Thanks for the replies. I would love to keep him in the tank as I think he's very cute and entertaining. I've even given him the common name of "Mr. Crabs" yeah I know real original hahaha. My husband on the other hand is not very fond of him as he ate almost all of the red algae on one of our pieces of live rock and it now appears as just a whitish colored rock instead of the pretty red one. Does anyone know if he will continue to eat all the red algae off of our rocks? I was hoping he wouldn't as I heard that's beneficial during the nitrogen cycle which we are currently just entering into being our tank has only been up approx. one week and the ammonia levels are just starting to rise but still well under control.
Being they are opportunistic feeder "yes" if they are not fed they can end up eating your coraline algea... You say it "turned white"...that sound like bleaching more so to me, not the crab eating it.
Coral bleaching is the name given to an event where coral expel their symbiotic algae due to extreme stress, such as drastic change in water temperature or lighting... etc.
Death can occur if the change is to extream or prolonged.
Coral bleaching is the name given to an event where coral expel their symbiotic algae due to extreme stress, such as drastic change in water temperature or lighting... etc.
Death can occur if the change is to extream or prolonged.
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