I just thaw it out in warm water and dish it out through a pipette. Any frozen food is good for conditioning if you ask me, but glassworms are too big for fry.
Its made out of rubber and you press the top so it sucks in liquid/food from the other end...it then holds the food/liquid in due to a vacumme. Then you squeeze it again and the liquid/food comes back out!
You can get pippettes like this with fish medication or you can use the medical measuring syringes that vets give you for giving your pets their medication.
I keep all the syringes that my old dog has for his medication (washed really well of course!).
I get my pipettes from Hobby Lobby, it's a craft store and they have a little science kit section that you can find them in. I'm sure there are other places too, I just wouldn't know where... I've seen them sold at specialty bird supply places as disposable baby bird feeders, and I bet you can get them at pharmacies. I get the plastic ones and cut the thinnest part of the tip off so it's easier to suck up bloodworms . I've been using the same one for months, I just get a new one when the old one starts to mold inside since they're practically impossible to clean.