oh no!!!!!! once it was cycled, did you add anything new right away? refresh us on the process as I dont remember all the details...my minds getting old
oh yes..oscars are huge waste producers in their bioload, and how they eat....both leave a ton ....I had to water change and vacuum every other day when I had my pair
in your size tank, 2 small ones a week wont hurt...half the tank one day then the other half another day....you have plenty of space just the oscars are piglets with their food LOL ...a bn pleco or one that stays on the smaller side might help with his food that he spits out....