Not sure what this grass is but it is growing across the entire pond, even the 12' depths. And algae, I think? Help please to identify and control would be greatly appreciated.

Given your LA location my guess would be najas or bushy pondweed.

I can't have tilipia in La, is there a natural way to get rid of it? If I fertilize my pond to try to get a algae bloom, will the fertilizer make that weed grow more? Thanks!

If it's bushy pondweed then grass carp will eat it. From the pics it's hard to tell what it is. Suggest take a small strand of it and place it on a plate for photo and maybe someone can let you know what it is.
Tp are more likely to eat FA, you know that green slimy snotty looking stuff Or you can go to TAMU Aquaplants for identification.