I have heard papilio is difficult, but some have had good success with them! They might be fussy about day length and temperature.
I didn't change the water nor put in bleach, only one went a bit smelly but that was seed from a hybrid which failed to germinate. The species behaved themselves and mostly floated on the water but some were a bit iffy trying to take a dive as they were growing so I propped them against the side of the tub. They don't get bleach in nature. H. striatum Petiolatum was one which wanted to take a dive, it didn't harm them though!
