Aggressiveness in Peppermint shrimp

[Fish Biscuit]

I'm new to the hobby and need some help. I have a 12 G nano cube. LR/LS, polyp & mushroom frags. No fish yet, started with inverts 3 weeks ago. Taking my time since the tank is little & when it's full, well it's full....

Went to the LFS and ended up w/ 2 peppermint shrimp, 2 hermit crabs, & 5 snails. Everyone was fine for the first 2 weeks & then I noticed some aggressiveness w/ one of the peppermints & it chased the other one out from under the rocks. Plenty of hiding spots, but he thought they should all be his. For 2 days this poor little shrimp was out in the open w/ no hiding sopt but was acting fine & eating. I had been giving mysis shrimp once a day, this is a tank at my office so nobody eats what they can't find on their own over the weekend.

I came in Monday am to find only 1 shrimp & half a body of the other. I'd like to have more than 1, but is this normal behavior in a small tank? Someone mentioned that I could've ended up w/ 2 males. Is it possible that with adding a little more LR & hiding places more than one would work out? I'm a little leary of adding fish if I have a monster in the tank. Checked pictures & it does apprear to be a peppermint & not a camelback.

Any help or suggestions would be greatly appreciated.

 

[Seventy]

Some shrimp can be tricky. I have 1 peppermint 11 sexy shrimp and 1 fire shrimp in a 40 gallon that have never messed with each other. I originally had 2 peppermints but one killed the other. I used to have a 29 gal with a peppermint and a cleaner shrimp and the cleaner killed the peppermint.

Usually shrimp vs shrimp is the problem, as far as fish and coral, I worry about the crabs more.

**edit**
Although I have seen peppermint shrimp eat polyps off of leathers when they get hungry.

 

[Fish Biscuit]

Thanks for the help & input. Went to a different LFS for RO water & he seemed to think the one was on the way out & that the other one sensed it. You never know with some of the LFS since they want to make a sale. When I bought the inverts the guy kept pushing me to buy fish because after he asked enough questions determined that my tank was ready for them. I'm taking the patient route, the tank has only been going for 2 months.

I've been doing research & read that shrimp don't play well with other shrimp too. I think I will stick w/ the 1 peppermint for now since there isn't a ton of room for everyone to stay away from each other. I thought maybe I had ended up with a monster, but time will tell.

The crabs are tiny so right now I don't worry about them bothering fish, probably 3/4 inch including the shell. Everyone is leaving the corals alone so I'm taking that as them having full bellies.