Prepare all vegetables by dicing thinly.
Place gefilte fish in sieve, and drain broth.
Place vegetables into warm skillet with oil. Sauté until vegetables are tender, but not done. Add sugar and pepper. Add diced tomatoes and water along with gefilte fish.
Stir gently until everything is incorporated and fish is covered with tomato broth. Cover and let simmer for half an hour. Serve warm, but tastes great cold as well!