Crab agression

[Horsegirl297]

So I have had two crabs for four months: Shelly and Sheldon. Yesterday I got a new one, Shawn. Shawn immediately burrowed under the substrate and we found him scraping the glass at the bottom today. We bathed him in saltwater along with our other crabs yesterday but they all went in separate directions so I'm not sure if they knew about him yet. Just now Shawn was up and walking towards the side of the tank with Shelly and Sheldon. I didn't see where Shawn was going, or if he just ran into Sheldon but they definitely started to interact. There was no chirping. However, Sheldon is larger than Shawn and got out of his shell to look big. His big claw poked at Shawn's smaller legs. I thought this was normal, but his claw was open and it seemed like he might be trying to get a hold of Shawn vs. just establish dominance. Sheldon totally blocked off Shawn's way. Poor Shawn looked terrified and was backing away as quick as he could, and Sheldon followed. I just put them on opposite sides of the tank. Is this normal behavior? Was Sheldon acting aggressively? Shawn is under a log by Shelly, but she didn't react so I think they are good. What should I do if this happens again in the future?

[Scarletfire]

When any new crabs get added to a tank, they need to re-establish the pecking order. Sometimes it takes a while. A few things to ask, what's the spec of your tank? Size, heating, food, water, shell, substrate, etc?

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[Horsegirl297]

I currently have a tank between 10-15 gallons, but I am planning on getting a 20-gallon tank in the spring when it is warm. I have two side-mounted UTHs (zoo med for 1-5 gallon tanks). My substrate is around five inches tall and once sand thaws some more I am adding two more inches. Half EE and half playsand. I use dechlorinated water and add instant ocean for saltwater. I feed a calcium supplement, freeze-dried shrimp, fresh fruits, fresh vegetables, eggshell, and occasionally egg. I have 6 shells of varying size in the tank right now.

[aussieJJDude]

It just sounds like a dominance display to me. Give them all time to adjust, and you'll find that these displays will be less common.

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