The blind cave tetra will probably push the neons around. They get much bigger and have a kind of rowdy attitude. I once encountered a shoal of hundreds of their colourful sighted version in Belize, and they chewed me from the ankles to the neck (I was in an inner tube being a tourist). It was the most beautiful spa day I can imagine, though I've never been to a spa. They're quick and at imes bossy fish (whether blind or sighted), and neons may not do well with them.