Kurt, you've also got at least 3 baby plants - No, there's 4! - in that pot. They certainly will grow slower with 3 in the pot. But they will grow, and since they've been somewhat traumatized this summer, you could wait until fall, or next spring to separate them each into their own pots.
I agree with keeping them wet. You can't overwater a colocasia. Plus they grow so fast that if you 'graduate' the pot size, you end up re-potting a big plant like that (should be) 4 times in a season. Once you see it starting to put up normal new leaves, you must start feeding it. At first go with half strength soluble fertilizer plus Mg every week, then as growth ramps up, go full strength.
Btw, your Thai Giant needs a BIG new pot, too . . .
They are hungry, thirsty, big lusty beasts.
Here's a graphic illustration for you - these are my Colo.Blue Hawaii which I divided a tub full of pups up about a month ago. As I realized I was going to run out of potting mix, I went to smaller and smaller pots. All these pups were about the same size a month ago. You can see how much more the one in the big pot grew. The one in the smallest pot was sitting in a saucer, so had some help with water but it's still about 8in. smaller than the one in the gallon pot. Give 'em a big pot and they'll grow to fit it!
