Aggression or Introduction?

[praecipuae]

Hello,

Apologies if this has been asked before. I have one crab who recently got a tank of her own due to the ones she was living with passing away, and after letting her molt found a suitable crab for her to live with. However, while introducing them, I noticed the new crab raising 2 of his legs (the ones on either side of his claws in the front) while keeping the rest flat on the ground. She responded by lifting her big claw (which was open) and starting to lift her own legs, at which point I tapped the glass which broke them up. They are both fed balanced diets with crab shell and organic food. Both crabs are the same species (Ecuadorian). She has never been aggressive before, so this is off behavior for her.

Any help is appreciated.

[curlysister]

Consider giving both crabs a quick dip in the fresh water - that way they will both smell the same and neither will seem like an interloper.

[wodesorel]

I've had bad luck with Es having continued aggression when housed together. Hopefully this was a one time thing as they had introductions. If it seems like they keep doing it, or are seeking each other out to start spats, please just be cautious. Maybe consider separating during molts. Many crabs will be harmless towards each other, but some Es are just awful roommates!