Mine really enjoy Fluval Bug Bites. They will also eat frozen bloodworms every couple of days when the frogs get them. I have never tried freeze dried ones, but maybe soaking them for a min so they sink would help? They are mid feeders mainly. It really only took a time or two of thawed bloodworms sinking past their school to figure out they are tasty. Now they will go down and steal from the frogs if they can.
I found that not only do freezedried bloodworms float but as they sink they look like fish poop. So I chop mine up in a little dish and soak it in fresh garlic put through my garlic press. (all fish go crazy for garlic) Then it looks like what they know food to look like and they are drawn to it by the smell.