Heat the oil in a pan over medium heat and cook all seafood until they are coated evenly. Season with salt and pepper and set aside.
Heat the butter in a same pan over low heat and saute onion until lightly browned. Add carrot and mushrooms and cook for 1 ~ 2 minutes.
Pour in water in the same pan and bring to a boil and simmer until the carrot are tender over medium heat.
Turn off the heat and add curry roux and lightly stir. Simmer again over low heat until thickened. Add seafood and stir to combine.