The largest fry are now approaching dime size, so you can see, they grow fast. BBS intake has about doubled over their first 5 wks. I only feed my fry once/day, unless I see they need more. Rather than relying on "people" to tell you how often they need to feed, watch them closely. That little orange/pink spot (their stomachs) should always be orange/pink and full looking, but give them time to digest before offering more. They will over stuff themselves if you let them. I don't promote "power feeding" in any species of animal to make them grow faster.
I don't know what your tank decor looks like currently. You can see in the photos that I allowed hair algae to take root and basically overrun the tank. Its not unpleasant looking really, but the reason I allowed it was to promote a natural food source (infusoria) for the fry to feed on between my offerings of BBS. This provides them the most natural diet and environment, and made it much easier for me to keep up with their near constant need for food. I have been working on weaning them from the BBS over the past wk, the larger ones will pick at the powdered flake, but its not enough to fill them up yet. In this way they are getting 2 meals/day along with the natural food source.
Watch your water quality close! When feeding BBS the waste levels will increase quickly. Algae growth can help keep the nutrient levels in check, but keep watch that it doesn't get out of hand... I have found a balance that keeps my nitrates at 10 or less at all times. The fry are very sensitive to fluctuations in water chemistry.
If you use a python hose for water changes, get a prefilter sponge to slide over the end of a filter intake tube that can hang on the side of the tank. It makes water changes fail safe for avoiding sucking up any fry and when the flow reverses back into the tank the fry can swim around it without being thrown by the strong water current. The fry are extremely curious by about the 2 - 3 wk point and will start to venture out to explore further away from the parents.
While watching my tank closely I have seen confirmed signs of communication between the parents and fry. The "warning" or "beware" signal is a fast twitching of the dorsal fin, its almost comical to watch. When its "emergency, hug the parents fast" then they tilt their bodies to the side and twitch all of their fins while swaying slowly back and forth. Its fascinating to watch how fast the fry respond.
As you can see, most of my fish are research projects. I run through a variety of "drills" to observe behaviors among other things. My 2nd pair has spawned yet again, (3rd time in less than 3 wks) refusing to give up, getting more persistent in their efforts.
My next research project begins when I take the fry from my successful parents and attempt a surrogacy of the other pair's eggs and then wigglers with the next spawns from the successful parents. I also have a pair of geophagus iporangensis that are spawning regularly. I have noticed there is about a 2 - 3 wk period of time where the geo fry look identical to the angel fry, so I plan to introduce surrogacy in both directions. I am counting the days now until the angel fry are moved to their own tank or leave for the store so I can push forward with the next project. I think I have finally figured out most of the timing and when I take each specie's fry determines how long until they spawn again... will be touchy but I think I can line them up within a day of each other.
Let me know if there's anything else I can do to help.