I love panda cories so I don’t see the problem here. Mom and Dad get some fun and your angelfish won’t let the spawn live for more than a day before they complete the Circle of Life.
I don’t have any angelfish. I don’t care for them, and anyway, I don’t think they like RO water. What I probably need is a loach that likes RO water.
ETA: my loach “Digger” eliminated my pest snail problem, because he loves him some snail eggs.
Had a kuhli loach that lived in the under-gravel filter and only came out to eat.
When I went from a 20 gallon to a 40 gallon, I didn’t need to cycle, because I used all the gravel, decorations, and plants from the old tank, plus, I put the old filter on the new tank along with the bigger filter. It was essentially like doing a 50% water change. I didn’t lose a single fish, or plant.
Using the old filter is a big deal. When I wanted to set up the old 20 gallon again as an RO tank, I used the old filter, with all its bacteria, and some plants and decorations from established tanks. I ran it for just a week, adding Seachem “starter” every day, and the added (hardy) fish. Didn’t lose one.
The beneficial bacteria does the work of starting up.
I low fish load helps.
A low fish load helps. 
It was a low fish load for a 40 gallon tank. High load for 20. That’s why I upgraded.
A panda-colored Corgi sounds adorable!
Well, they’ve done it again. The two from the last “litter” or whatever are about 1.5cm, and now some teeny-tiny little corys have shown up. They’re about 5mm long. I tried to catch the 1.5cm fish to take them to them store, and couldn’t get them. I’m going to have to take all the decorations, and possibly the plants out in order to catch them.
I think I figured out what I must’ve done, though. About 3 months ago I put in a plant with broad leaves that the corys like to sit on. That’s probably where they are laying.
I believe it is a “spawning”. 
I am surprised that you take them to the pet store when they are so small. I would want to watch them grow up, following their parents around like baby ducks.
Panda corys don’t get as big as other corys, so that’s actually pretty big. I don’t want them to get so big that I lose track of which ones the new ones are.
You amaze me, Sir.
The first two went off to the fish store a while ago. Right now I have one that is about 1.25cm, three that are about 6mm, and four or five that are teeny-tiny. I’m feeding cory pellets, freeze-dried brine shrimp larvae, and a high-quality flake food. There are tetras and rasboras in the tank as well, who are not spawning, thank goodness.