however (and don't take it personally, I'm just letting you know!)
The common plec is going to outgrow a 55g, I'm afraid
White clouds are shoalers, so one won't be very happy; they also need lower temperatures than the other fish.
Frogs really don't do well in fish tanks. They have very poor eyesight and struggle to find enough food before the fish get to it.
If it's a male platy you'll be ok, but if it's a female, she might be pregnant and will have a lot of babies that will grow up and have even more babies (though your other fish, especially the mollies will eat at least some of them.
At least your not overstocked, apart from the plec!
Yeah, I'll cross that bridge when I get there. Right now he's maybe 2 1/2-3 inches and the 55 is a big step up from the 10 gallon. I might just have to adopt him out at that point.