not trying to steal the topic... but uptill now I bought my fish from the fishunion in Los Charamicos, as you can get fresh fish there (not frozen). I also saw a new fishplace, in the small street from the small Playero, to the big Playero in Sosua.
To the OP... what I have also done is gone to Kiosko beach and asked Johnny when his fishguy came and his phonenumber. The fishguy, Johnny Pescador, is reliable, has good prices and very fresh fish. I lost his phonenumber as I switched phones and data got lost. If you call him, you can even try to order certain fish the day before, and if he catches them he keeps them for you.
BelgianK