How Many Shrimp Can I Have In A 20g Long?

My current set up is 7 guppies, three albino cory and one lace cat and two ghost shrimp.
After learning more my set up WILL SOON BE three guppies, six albino cory, two ghost shrimp.
I got my two ghost shrimp last week to see how they would do with my guppies before I bought the more expensive Japanese Algea eating shrimp, I heard ghost were sensitive and die off quickly but my two are doing great, active and one just had her babies.
Going forward I want to get the more expensive shrimp but will still keep my two ghost.
So in a 20 long with three guppes, six albino cory and two ghost shrimp, how many Japanese Algea eating shrimp would I be able to keep comfortably?

 

8 is a good round number. that way you still have places to hide for them and they won't bother the other fish too much

 

8+ the ghost I already have or 8 including then two I already have?

 

go with 8 total

 

Will they bother each other if there's that many though? As weird as question may sound my two ghost shrimp are both female, one is still carrying her eggs but anytime that get to close it looks like they are boxing each other and then one runs away. Is that fighting or normal behavior? (I've never owned shrimp before).

 

that sounds aggressive, but you will have agrression diverted in a tank with more shrimp instead of just the one getting picked on