the prices in red mean the price has dropped, in green - the price has gone up from where it was.
The ticker is delayed 15 minutes, and should not be used to base your buying and selling decisions on...it's more for 'show' than for actual "instant" information. Also the "quantities" shown in the transactions do not indicate "how many" shares were purchased, just that THAT particular purchase was shown....
Basically, it's for 'cosmetic' purposes to HSX and not for relying on it for trades....