A good question, but I don't know the answer. I checked the USDA Database for 100 gram portions.

Radishes, oriental, cooked, boiled, drained, without salt 3.43 g Fiber: 1.60 g

Radishes, oriental, raw 4.11 g Fiber: 1.60 g

Interesting! Perhaps someone will come along who can shed some light on this.

Karen