Ohhhkay.
There are two separate clauses here:
"Ceterum censeo" and "Carthago delenda est".
Ceterum cenceo -> Carthago delenda est.
No, there is no need for a comma, because it works just as it does in English:
"I think Carthage should be destroyed", not: "I think, Carthage should be destroyed".
Oddly, it doesn't work that way in Portuguese, where we must add a "that" between the two clauses. But the comma isn't necessary for Latin and wouldn't make sense for it.