In my sorrow, I copied and pasted this from a foodie blog :
Where the claim takes a surprising turn is when the proprietor
of a halal Chinese Restaurant, a certain Mr Ng asserted that it was
him that actually came up with such a dish in the early 50’s after
experimenting with the curry mix when he was a stall helper in the
vicinity of Indian restaurants that he learned from to how make a
curry. Offering a less spicier version in his restaurant called Our
Makan Shop, the curry actually looked like the typical Nyonya or
Straits Chinese curry prevalent in the region. It is not a surprise
that the Nyonyas after centuries of assimilation managed to develop
their own curry version, but Mr Ng offered no reason why he was
inspired to serve fish head in curry form as an original dish or
why it was he alone who tinkered with such a concoction. As I am no
Nyonya culture expert, I am unable to ascertain if Nyonya food has
featured fish curry as a recent invention or it has a been
generational food inherited through the ages as it should be. In
addition, I have seen fish head dishes as a gourmand delicacy in
mainland china, so I do not think it takes a long stretch of
imagination for the Chinese of the region to turn the fish head
into a curry dish in a version of their own down the ages.