Rule for stocking shrimp

Mine have never climbed out of the tank or even tried. I change the water weekly and sometimes mid-week if it looks like it could use it. I keep my level right to the top.
 
I can get them from a wholesaler :) '100 amano shrimp, £30.00' Or whatever. Or fifty cherries, 10 amanos, and then I can get 40 of my choice like yellow or crystal.
Man I'm getting a bit carried away here ;)
 
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