Excuse the mess of the tank, took this photo while I was removing plants to add more gravel and stuff, so I'd stirred everything up and it was everywhere including all over the sponge filter. I'd also tried (and failed) to grow a proper algae wall for the shrimp.
But see the mass of hornwort floating at the top right corner? That's basically my guppy fry nursery. Mine is planted, but I let it get into a long mass at the top for the fry. They all tend to congregate in there, although I usually have a stone or "tree" with masses of java moss low down too, plus other plants like crypts and swords.
But you can use anything. My first batch of fry I thought I was prepared because my tank had a lot of live plants, but I panicked when they were born since they all went to the surface in one corner, and my plants were all too short! I went to LFS and found some silk leaved fake plants he was selling off for a pound each, so I got three or four of them, and wedged them into a suction cup and stuck that the side at the top, and they all hid in there. Worked perfectly! Every time an adult got close, the fry would just move around the leaves and hide, and I fed them in there. I didn't take a photo of that, should have, but have kept the fake plants for quarantine use since they can be bleached. Might add them to the 57 G community tank later and snap a photo, since the elodea in there died after I medicated the tank.
Any plants that float and have roots work, like frogbit, water lettuce etc, and stem plants like hornwort or elodea (like in this pic) are probably even better since they form these tangled, long and deep masses of stems, which fry can get around easily, but bigger fish like your angels will struggle to navigate quickly. Guppy grass is recommended a lot too, just see what's available near you, and use fake if you prefer!
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You've clearly been feeding them well and keeping their water nice and clean, good job 
