1 gallon jar saltwater

Ah ok. My life isnt going good right now but the jar is thriving! Theres a couple live barnacles I didn't notice before and theres a bazillion baby scuds

Update time! I missed a day of testing and there was an ammonia spike. All better now though.

The lid of the jar was rusting and dripping into the water so I moved them to a different 1 gallon that I had around.

Oops the crab seems to be doing well. He/she is so fun to watch. It likes to hang upside down on the artificial plant I put in there for it to climb on and wait and try to catch the scuds. I have a few pictures, sorry they are blurry!