Here's the scoop on mixing Platies and Goldfish mixing.
They could mix and do alright, until the goldfish are large enough to eat the platies. They will almost always eat them as soon as they are large enough to do so. However, platies are tropical fish and do their BEST in temperatures that are within their natural range of mid to upper 70s.
(We have a juvenile goldfish in a 55g with a snow king pleco and several dozen feeder guppies.) The tank ranges anywhere from lower to upper 70s and everything runs smoothly, but I must add to this that Dino has decades of fishkeeping experience, a bachelors degree in biology, and I have been keeping fish for 2 years. We know what we're doing and wouldn't necessarily advise most people to keep goldfish with some of the more hardy tropicals. It can be done, but the tropicals will not thrive as well as they could if they were in a tropical temperature setting.)
I hope that is clear enough to be understood as saying, "It is possible but not advised."
If anything the angelfish would eat the platy and sword fry rather than the platies and swords being likely to bother the angels, but that is my opinion.
