Beware of the Ghost Shrimp!
I bought 6 ghost shrimp, cute as can be, and put them into my tank with my beautiful bettas, cories, etc.... i came in, saw 1 fish damaged, thought it was from my betta. This morning, woke up, found her dead. Found another fish dead and half eaten. Upon research, Ghost shrimp killed them. Ghost shrimp will eat sleeping, injured and dead fish... dead fish, i'm fine with... Sleeping? Nope! They are also known to eat their own kind AND capture slower swimming fish and eat them... like fancy guppies, they grab their tails....
That's the LAST TIME i buy a fish without researching!