I've never kept blind cave tetras because they have a reputation of being very aggressive. & I bet it's worse with only 1. They're said to be best in a species only tank...& iffy then.
Can you give it back to your LFS? Then get something more compatible. To help you decide what may be a better fit, tell what size is your tank?...etc...everything!
I had 3 of these and never saw them attack another fish. I did not keep shrimp in the tank however.
Do the fish have damaged fins? Are shrimp dissapearing?