And I agree with Joe.
How nice it is, if people agree with each other.
It's very interesting to hear, that they will also eat small fish.
I breed all the food items myself, because there's no available supply of feeder insects in my country.
I breed three species of crickets, two species of mealworms and two species of roaches.
It's a lot of work, but I have no other choice and always all sizes of well fed insects available.
I also bred fruit flies, but it was just for baby klemmeri and I stopped, when I found out that even new born klemmeri babies are eating very small crickets without problems.
The adults can eat rather big crickets, but I think they prefer smaller ones.
If the cricket is too big, they can grab it and kill it and not always eat it.
A German friend of mine, who I originally got my klemmeri from, also fed his klemmeri with these little "silver fish" insects (or what are they called?).
He actually brought some a bit bigger species from Madagascar and bred them. They didn't climb or jump.
Klemmeri liked to eat them.
If you order very small crickets and not keep them too warm, they will grow slower and you can use them for a longer time.
Just feed them quality food.
Matjaz