New update: all 5 fry are going strong, but they are now stupidly courageous. At first it was only the runt that swam off and explored, but now the other four have gotten some wanderlust and are exploring the gravel-based plant underneath their floating plants. The platy will half-heartedly go for the fry, but they never pursue once the fry has gone behind a plant. I think they've learned that the evil Ms. Finger will chase them off if they try.
Strangely, the little runt has started schooling with the
CAE XD If the CAE gets close to the floating plants, the littlest fry will follow him around until the CAE goes back to the other half of the tank.
I'm expecting another batch from the female sword any time, as the fry are five weeks old now. The female platy looks like she, too, is ready to have her fry- she's a very pale pineapple, so I can see through her scales to see the eggs developing inside her. They've grown a lot, and I think they'll hatch pretty soon.