I have 6 neon tetras in a 10 gallon tank and would like to add a good bottom feeder as my neons only eat mid level. I've heard Cherry Shrimp are great bottom feeders and live well with neons. My question is this... Can I just get one cherry shrimp or is it better to have more than one? If it's better to have more than one, how many would you suggest for my tank? Thank you!