Cories typically like to hang out together. My 9 cories bunch up in almost a dogpile in my 50 gallon tank.

I don't know what to recommend. Like I said, my cories change behavior for things I did not think we're significant at all.

Maybe post pictures? Sometimes experts (I am not one) can spot ...

I would agree that one of the pygmy Corydoras varieties may be a better fit for a 10 gallon with shrimp, especially if you're a beginner and prone to lapses in dilligent tank maintenance. Less bio-load in your tank means it can withstand beginner mistakes better.

I would not say your tank is ...