You don't need a poaching pan to poach fish; your roasting tin will do just as well. Place the fish on the rack, cover with water or stock, and barely simmer for 10 minutes per inch of thickness at the middle.
To keep a poached fish from breaking as you transfer it from cooking pan to serving dish, cook it on muslin or greased aluminium foil. Cover the rack of the poacher or roasting pan, making sure enough material extends over the edge so that you can get a good grip. Hold the material taut as you lift the fish from the pan and slide or roll it onto a serving dish.
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