Gotta a Mean Aggressive Crab in my Tank!

[rayyne99]

I have had him for over a year... and he was one of the original 3 crabs I purchased.

HE is the largest crab out of the 5 currently living in the tank.

And for some reason, he starts to focus in on 1 or 2 particular ones, and is constantly harrassing & intimidating the heck out of them.

He will come over from across the aquarium, and stand really still in front of the other crab, so they can't move. Then out of the blue... he literally "socks" them really hard with his big claw!

Sometimes 2 or three times in a row.

How am I supposed to handle this situation.

All of the other crabs...........pretty much stay in hiding now... probably dreading the minute he decides to cruise around, and torment them.

Anybody have any ideas???

Your suggestions would be greatly welcomed...

take care and thanks a million

[CrabbyJo]

Rayyne,
A change in behavior can often indicate pre molt symptoms. Even if he hasn't behaved this way before a molt before, he still can portray a different personality due to the changes going on in his little crabby body. (Sounds like puberty lol).

If I were you, I'd set him up a nice isolation tank (one he can stay in for a long period if he does end up molting, so no kritter keeper, which should only ever be used in emergency isolation cases) that's stabilized with temp and humidity so give it a couple days after setting up to make sure it's close to the main tank temp and humidity, and move him over. Make him nice and comfy, with the regular dechlor fresh pond and a good sized ocean salt water pond (if he is premolt, you may be filling the ocean water a lot) and a hidey or two and some greenery to hide in too.

Don't bother him too much in there, and if he doesn't molt in a few weeks, and isnt' portraying symptoms, you can try returning him to the main tank to see if he's gotten a different attitude from his "time out".

[emmac350]

It sounds a lot like typical 'dominance' behavior. My crabs haven't done it in front of me, but I've heard of others' crabs doing the same sort of thing when they introduce new guys to the tank. If the crab still does this sort of behavior after molting (if indeed he needs to molt), try feeding all of your crabs more protein and calcium. Some aggression can be remedied by daily meat in the food bowl (don't stop feeding the other stuff, like fruits and veggies, cellulose, seaweed, etc.), so it's worth a shot. If you do feed larger pieces of meat, cut them into pieces beforehand so he won't steal the only piece from everybody else.

[ladybug15057]

Sometimes even with a well balanced diet a hermie will become crabby with pms.
My King Kong did this once as one of his pms's and was the only one he displayed. He turned his brother Donkey Kong upside down and was pinching in at him. (with over 20 other turbo shells in the tank) Donkey Kong chirped so loud I took King Kong off of him twice only to hear his other brother Clyde to chirp out next. I removed King Kong from him as well but put him in iso. Took the hut he favored with a little of the substrate from the main tank and put it where I was putting the hut. King Kong ate a little, went to both ponds and then to the hut not to come back out for awhile. He molted, recovered and was the sweet little Jumbo he was prior to his pms's.

[Wai]

Generally, the pushing and shoving with claws is harmless, but if it results in a shell fight, it can get pretty nasty.

Mid last year, I was in a rush to eat dinner after coming home late with Sedna. I didn't have food and water in the isolation tank at the time (since it was unoccupied), so I left Sedna in the main tank to stroll around for a while until I finished dinner. A few minutes into the dinner, I decided to check on Sedna and was absolutely alarmed to see her naked after Haumea had already kicked her out of her shell. Haumea was still looking into Sedna's shell at the time and hadn't tried it on, but I pulled Haumea away from Sedna's shell and gave her an angry look lol. Luckily, Sedna moved into a nearby shell soon after, but I could tell she was traumatised.

[ladybug15057]

Wai is correct. As long as it is pushing and shoving as well an antenna 'fencing' this could be the hermies establishing pecking order. However, when one sees large pincher action (as in pinching out, or pinching) the aggressive hermie should be iso'ed for a spell for a time out.