female betta fish

Question
why does my female betta fish have a white string hanging from her belly? she was brown now shes bright red?

Answer
Claudette,

 Describe this white string. How long is it? Where in her belly is it? If its a white tube looking thing, called the Ovipositor, then that is her way of showing she has eggs. As for the color change, that happens as they get older. As long as she is swimming and eating good and acting the same, I wouldn't worry too much about it. Just keep an eye on her and if there are any changes let me know.