African dwarf frogs are extremely challenging to own because of the feeding aspect. They're almost completely blind and hunt by smell, so in the race to get food from the surface, the frogs will always lose against the betta.
I don't recommend feeding freeze-dried blood worms to either animal as a staple. You should really do more research into the dietary needs of ADFs. What a lot of people do with poor-sighted fish and other critters is to designate a certain spot on the bottom of the tank for feeding. You can put a small dish or a flat rock on the bottom and set the food in the same place every time. Eventually the frogs will learn to go to the same spot to eat every day--however, in order for this to happen you will probably have to put the betta in a cup during feedings, or leave him netted in the tank so that the frogs will have access to food.
Did the tank undergo the nitrogen cycle before you put them in? Frogs are very sensitive to ammonia and changes in water parameters. They are not good candidates at all for fish-in cycling and the 100% change method would not be a good long-term solution for such sensitive animals.. if the tank isn't already cycled, I think you should consider keeping them in a temporary container, such as a sterilite or rubbermaid storage bin while the tank is cycling. These bins are only about $3 for a 5 gallon container--you'd only have to change it about once a week while your other tank is cycling.
Last edited by Adastra; 09-14-2010 at 05:53 PM.