I going to use gloves, you can never imagine how much bristles are left on my LR by my unlimited amount of Bristleworms.. Your whole palm will be full of bristle when you handle my rocks..
The transferring and the fluctuation may have a part in why the two angels are dead this morning..
But you will still need to introduce slowly into your tank.. Sure will be in the betta tank for a period of 1-2 week one mah.. Unless you wan them to fend for themselves in the tank..