Found this thread months after getting my african dwarf frogs and i love them to bits. Most of the knowledge i have is from personal experience and bits and bobs i have learnt from other enthusiasts. I am probably not the most knowledged on the subject but will try to help.....
Feeding Yes, frogs are very docile and could do with much better eye sight so they can easily be beaten to the food by fish. They seem to benefit from the frozen (ice cube lookng) foods such as bloodworm and daphnia etc. I find if you leave the cube in a small bowl of warm water on top of the tank so it will defrost, it seems to be the best way to make sure some gets to the bottom. Before frogs i used to just chuck the cube in and watch the feeding frenzy but if you do that, the fish get all the food.
If after trying the defrosting method you are still having trouble, pour the food infront of the filter outake. I have a waterfall type contraption which naturally forces the food downwards and to also dispurse throughout the lower tank area.
Failing this, or just for fun- Over time and with practice you can actually train your frogs to react to your fingers movements. I started by gently tapping the glass to get the frogs attention. When it comes closer you can try and direct the frog around the tank by running your finger around the outside. Remember, as the frogs have a poor vision i think it works best by moving your fingers slowly, as they may be able to see the shape difference/ movement better. By doing this you can get a sort of routine going by directing them to a regular place where the food is normally forced to go before you put it in.
You can also try to hand feed the frogs but i recommend you try to get them used to your fingers by the above method first. Again, keep the routine of getting them to the established 'feeding point' first.
Hope this helps, Sorry about the spelling (it is late). I log on pretty frequently so if you have any other frog related questions feel free to leave them here and i will try help best i can
Enjoy your frogs