Hopefully Ted and/or Carey or other experts from 'up yonder' will chime in.If properly sized, the aerator should have turned the pond over several times and oxygenated it by now.(May be latent low O2 death) If the visibility has been diminished, it may be that the stones are stirring up the sediment. Let us know how they are set up. They should be off the bottom, on platforms etc. to prevent stirring up the bottom sediments too much. It may be better in you part of the country for some stratification to occur to keep low temps. for the trout. Take temp readings at various depths and report. . Those are a lot of kinds of fish to deep happy, but should be able to be accomplished.