I'm not too sure about Oceanside, but if you're willing to drive 30 minutes down to San Diego, there is Pet Kingdom in Point Loma (on Sports Arena Blvd), and Fountains in Le Mesa (on University). Pet Kingdom has an alright selection, but I don't care for the employees. Fountains Is pretty good and I have no complaints about the staff there.
hi bro
glad to see another SD bro around here

those lfs have awsome fishes