A good way to hatch the angle fry is to remove the eggs from the parents and that tank, put them in a 10 gallon bare bottom tank. In the 10 gallon tank you will need a air operated spung filter, an air stone, heater. Place the spung filter in a corner of the 10 gallon and place the tube with the eggs on the other side of tank and stick it to the side of tank off the bottom just the way it is now. Place the air stone under the eggs and gently let the bubbles rise up over the eggs. After the fry hatch they will wiggle and come off. Do not start feeding them untill the fry are swimming freely and feed the frozen baby brine shrimp, you can get that at the pet store.
You might want to try placing a cone, a clay pot or a smooth peace of slate in the aquarium for them to lay there eggs on, much easyer to move into hatching tank. It is ok to remove the eggs from the tank it will not harm them. Keep the water clean. Do not use water from the aquarium that the eggs were layed in. More offten than not the parents will eat the fry.