How many different people directed the episode titled "Fail Fish"?
CREATE TABLE "table1_28146944_2" (
  "no_in_series" real,
  "title" text,
  "directed_by" text,
  "story_storyboards_by" text,
  "original_air_date" text,
  "u_s_viewers_millions" text
);
SELECT COUNT("directed_by") FROM "table1_28146944_2" WHERE "title"='\"Fail Fish\"';