So try this, use the pinch of food you usually feed and divide it in two and feed a little every day. Chances are that these little guys are still young and would benefit from regular good nutrition, if they were in the wild they could scout around for food any time they got hungry, but since they are in a fish tank they need to wait for you to give them food.
It is hard to be sure about not feeding enough or too much. Except you can test the water to make sure there isn't too much ammonia, and then also watch for the food that isn't eaten.
For example if you add one pinch of food all at once, some of the food will get hit by the water current and sink faster than the fish can zoom around and eat it. So it might end up laying around.
If you add a flake or 2 to get their attention, and then they know you are there to feed them, they will come over to see what is going on because of the smell of the food.
Then when you have their attention, start by adding a little on each side of the tank and let them eat it, then a little more, let them eat it, and so on until they aren't too interested. If they let food hit the bottom they may full. You would only be feeding them for a couple or 3 minutes though.
But for your bottom feeder, try the Hikari Sinking Wafers for botton feeders and add one (or a half of one) to an area which he normally hangs out in. The other fish might want to get down there and try eating that too. Just make sure he gets some food to eat. I bet they all love the Blood Worms!
You can always plan the pwc to be awhile after the fish get fed (especially Blood worms though they probably eat those right up!)
