I feed mine microworms mostly from the first days. Vinegar eels are also useable.
One of the things one also has to remember is to feed well, more times a day is good.
Just last week I seperated some p. tweediei, which had been very inactive for a year at least, – 2 males and 3 females in a bigger tank. No activity at all.
Then I seperated them into pairs in small tanks, and the next day one of the couples had eggs. I was also able to follow the development, so once they were free swimming but still in the cave, I took out the male and female.
So I expect also to have some p. tweedieis soon :)… I can see them dart around, in particular before the light is on, and if I look into the tank with a flash light.