Sudden Fighting after Two Years - Who to Iso?

[Mirrorakay]

So I've got myself a bit of a problem. Gaia, an E, and Zeus, a PP, suddenly started fighting a few days ago. I'm not entirely sure how it happened. They've been happy tank mates for years now, but on Friday of last week something change. I woke up in the middle of the night to Gaia chirping. I found that Zeus was rolled over on his back, his big pincher clamped down on Gaia's leg. It took a minute or two, but Zeus finally released Gaia and everything was alright. Gaia's leg did have an injury on it, down on the very tip, but otherwise she seemed fine. The leg still looks to be in good shape now.

However, that set off a major problem. Gaia is now actively hunting Zeus around the tank. She climbs up on his shell. Zeus sits as chirps. Up until last night, she would simply sit on his shell. Then, when I woke up this morning, Zeus was chirping again. When I move Gaia off him, he came out of his shell with two pinch marks on his big pincher and one on the far leg that faces out when he tucks in his shell.

Both crabs are still on good terms with all of the other crabs. Gaia is only fighting with Zeus and while Zeus now chirps frantically if anyone stumbles over him, he's not being attacked by anyone else. I've never had this problem before. I know I need to ISO someone, but I don't know which. The attacker or the attacked? Both have very minor injuries. I only have one iso tank on hand so I can't iso both. What do I do if they never repair their bond?

I know you guys will ask, so here's tank info:
Tank is 55 gallons
Temp 80F
Humidity 75-80%
Substrate Eco/Sand Mix 12 inches deep
Gaia is on the small side of medium
Zeus is on the brink of being large
There are 10 crabs
40 clean shells are available - four shells for each crab's specific size
Clean freshwater and instant ocean salt water
Food is swapped daily. They get fresh protein daily.
Gaia's last molt was about two months ago
Zeus's last molt was about one month ago

[hermitcrab24]

I am by no means a hermit crab expert. I have never experienced fighting, but I will give you my opinion. I feel if Zeus is paranoid and is chirping when anyone stumbles over him, then you should iso him. That will give him a break, and since Gaia is not hunting anyone else, she will probably be fine with the other crabs.

Good Luck,
Bonnie

[wodesorel]

Given that she's the E, I'd probably ISO Gaia for a while, maybe until she molts again. But I've had bad luck with Es and I admit I'm biased.

[jarteta97]

I agree with Wode. I've also had bad luck with E's

[Mirrorakay]

I should also mention this is not the first time Gaia has given me trouble. Two years ago, when I first got her, I got her with another E. The other E was torn to shreds about a week after adoption. I figured it was a surface molt gone wrong or something. A little while later I got another E. This one was buried when it was attacked. I waited several months and adopted a third E. This one I actually saw Gaia kill. I strong suspect Gaia killed those other two as well. Ever since that, Gaia has been a wonderful tank mate.

I think I'll probably end up putting Gaia in ISO. I think Zeus will settle in a day or two, but I really don't think she will.

[Mirrorakay]

Gaia is officially in the time-out tank. I was thinking about leaving her for a week and then reintroducing her. Is that too soon? I've never had to isolate for aggression before so any advice on reintroduction is much appreciated.