Spaghetti worms!!!!

Hi all! I am new to this forum and relatively new to this obsession. I have a quick question (questions) about spaghetti worms. I have about 5 in a 29 biocube. I'm not really happy with how they look but I have read that they are beneficial. My question is how fast do they grow and when do I start population control? Is manual removal the only way to get rid of them or is there some wonderful creature that will keep their numbers in check. Thank you in advance.