Are we talking about red cherry shrimp.
Never kept mine with tetras, but my understanding is that many tetras will chow down on shrimp fry. The java moss will certainly help, but I'd be a little worried.
Oh, and I'd add that you can start with as little as 10 RCS, though with other fish in the tank it may not be enough to get a colony going. Almost any fish will eat shrimp fry, some more eagerly than others.
Never kept mine with tetras, but my understanding is that many tetras will chow down on shrimp fry. The java moss will certainly help, but I'd be a little worried.
Oh, and I'd add that you can start with as little as 10 RCS, though with other fish in the tank it may not be enough to get a colony going. Almost any fish will eat shrimp fry, some more eagerly than others.