Pathos,
Before putting the bottle in your tank, make a small feeder and feed them for a couple weeks or so. you can use a pouch made of window material screening or a netting material . Put a piece of shrimp or fish in the pouch along with a couple stainles steel nuts,screws or rock to sink the pouch . tie it shut, drop it in the tank when lights are off with some fishing line tied to it for easy retrieval in the morning .after a few days they'll take no time getting over to the food .
When you feel its time , Put the pouch in the bottle,thread the fishing line up through the mouth , strip tie the bottle together and Drop it in . I used a regular size plastic soda bottle instead of the 2 liter and strip tied the inverted lid .
In minutes the shrimp start to figure out how to get the food . When one or both get in the bottle just start retrieving .The fishing line pulls the food pouch with the stainless steel screws,nuts or rock in it,up against the mouth of the bottle trapping the shrimp as your pulling the bottle out .
You'll have them in no time in your sump or back to your lfs .
I cought all three in my 125gl. in less than 30 minutes .