Three rapid response vehicles and five emergency ambulances were sent to the scene, where there were "multiple casualties", a spokeswoman for Welsh Ambulance Services NHS Trust said.
She added the ambulance service was called to the single vehicle collision at about 8.55am this morning.
More top news
The youngest royal will make her second public appearance later this afternoon when she is baptised in Norfolk.
Jayln Rippy died and her mother and brother were seriously injured by the fish, which can grow up to eight feet long.
European nations are collectively consuming more fish than its waters can provide, according to a new study.