Generally you'll find two schools of thought on this: some say they don't do well with fish, others say go for it. My opinion is that you should do what you think is best.
A general rule of thumb would be to only introduce fish that are #1- compatible with your water temps and ph, #2- are social fish, and #3- larger than your frogs.
Anything smaller than your frog is going to be seen as a food item and aggressive fish may fight with your frog or visa versa; ie: don't put a betta fish or an oscar in the tank.
Some ideas for fish would be algae eaters and fish that feed off the bottom of the tank. Loaches, 'wall-sucker' fish, tetras, bala sharks, even a gold fish or two(but they can be quite messy)may work for you. Just be sure to watch for overcrowding, you need to regulate the ph for the frogs and too many fish or sick fish can quickly alter that and cause harmful problems.
I'm sure if you ask the clerk at your local pet store or pet supply chain they will be able to recommend some other 'social fish'.
I hope this helps! Good luck with your frogs!