There is always a spoilt sport here. Let me be one, hehehe!
$400 - can get live fish from kelong - $10-$15 per kg for red snapper or garouper - guaranteed got catch. They keep their catch under the kelong. You are lucky only when the kept fish escape and loiter around kelong.
Not to forget renting the fishing boat, about $600 - $800 whole day only in Singapore waters (2 years ago). In Malaysia nearby Pengarang-Sg Ringit area - off Changi - rental boat about RM1,500 day fishing. Waters around Singapore mainland and islands not good for fishing because of land reclamation, cloudy water and shipping.
For first timer or occasional fisherman, hand reels are good enough. No need to feel pai seh. Can feel bites with naked fingers - even the smallest fish. Malay and Indon boatmen-cum-deckhands use them and usually catch more fish than those using expensive rods.
Finally, even calm season in June-September period, South China Sea can be choppy. Before you reach destination off-shore, kepala already pusing and you may be feeding the fish with your morning breakfast. Motion-sickness pills can help but just a bit.
Why fish? Let the big fish have their freedom and enjoy the sea breeze under the coconut tree or casuarinas. You get more peace of mind than anxiety. May be try experience watching the night sky from a kelong off Punggol in Malaysian water. Kelong owner provides steamboat and BBQ and mattresses if tired. Like I said, spend whole nite there with few fish - but the experience is worthwhile with not-too-demanding kakis (sorry lost contact already).
Finally, there are bigger fish awaiting you at RWS and MBS - just bring more than $400. Enjoy your trip!