Could you post a picture of your Halymenia? Is your Dragons Breath soft & slippery? I find the Pacific variety, Halymenia digitata, more durable compared to the Gulf of Mexico variety.
https://www.live-plants.com/redsealettuce.htm
“Species of Halymenia are gelatinous, smooth in texture and are very delicate. We collect two varieties, H. floresia & H. floridana. One features long flowing fronds while the other is more compact with rounded edges. They require good water quality and moderate to high flow to maintain their slippery, fleshy blades. This species is a bright red coloration with no iridescence at the tips as the Pacific halymenia species have. We ship a portion that is approx 6"- 8".”