how to poach fish

How to poach an 8 oz fish filet

2 Tab lemon juice(opt)
1 qt water,
1 c. onions,
1/2 c. carrots,
1/2 c. celery,
3 ea bay leaves,
1 cup dry white wine(opt) and no cooking wines,
1 1/2 tsp sea salt,
1/4 tsp white pepper,
3/4 c. fresh tomato(opt)