For the banana fish stew, wash and dry the fish and sprinkle with lemon juice. Rub with a mixture of salt, pepper and curry and set aside.
Peel and dice the onion and sauté in a little butter until translucent. Peel, dice and add bananas. Dice fish and sauté in the pan.
Deglaze with sour cream, season with curry, salt and pepper. Bind with cornstarch, bring to the boil briefly and serve the banana fish stew immediately.