I haven't run my Hexagontchi yet, but from what others have posted, I think the growth stage times are the same as on the TMGC+C.
Here is how long each growth stage lasts on a TMGC+C:
Egg + 1 minute = Baby
Baby + 1 hour = Toddler
Toddler + 24 hours (1 day) = Teen
Teen + 48 hours (2 days) = Adult
Adult + 2 sunrises = now can mate
Adult + 168 hours (7 days) = Senior
Note: the child of a senior grows from baby to adult in 1 hour, skipping the toddler and teen stages.