Ensuring your frog has adequate hiding space may or may not help. Unfortunately, little frog feet often look like enticing fish food. Sometimes fish ignore frogs other times there are problems like you experience. I have frogs with a few miscellaneous tetras and rhasboras, and I have no problems. It may be my fish have a better temperment, or it may be because I have six frogs and 8 fish. Good luck!
\Dan