Banded Coral Shrimp - Boxing Shrimp

 Too soon? Too big? Yikes.

Did I make a mistake?

These questions have been flooding me the last 12 hours. 

Yesterday, I had decided to take action on these flatworms and wanted to do so without having to intervene with a baster every day to pull them out. 

My tank is too small for fish, 5 gallons. So my next best move was another invertebrate and landed on Banded Coral Shrimp. Their antennae is quite long and has me worried most. My tank does not feel spacious for him.

I think I may start my 2nd tank upon getting a new job. I'm thinking upwards of 20 gallons.
An urchin is definitely on my list for that setup. And a wrasse and other harmful critter eaters which can be used in the smaller tank.