Also later in Space Patrol Luluco, we find out fire is Life Fibers' weakness.
...Ryuko.Hmm? What is it, Senketsu?Would you have named meWhat?If That had happened when you and I met...Keiketsu insteaaaaAAAAAAAAHHHHHHHHHKeiketsu (経血) is Japanese for 'menstrual blood', whereas Senketsu is 'fresh blood'.