I was wondering how much cover you have in the pond and how many predators you have. Tilapia in the belly of a Bass cant clean much grass. Algae didn't rhyme.
I have a new pond without any predators except CC. I put 10 # of large tilapia 11 weeks ago. I have had literally thousands of fry. The original spawn are now 5" and have spawned themselves. My limited experience with them leads me to believe they are not that good at avoiding predators. The first spawn swim in schools of dozens. One of the large originals was white. These offspring are so easy to spot that they are bound to be easy fodder. You can see them so easy that the darker cousins look like shadows swimming with them. My CC have quit eating completely. I believe their belly's are full of tilapia. I think the small tilapia fry would be quickly devoured in a pond with enough BG to boil the water. My water boils with tilapia when I feed. Have you done a seine survey to see what kind of numbers of original tilapia you have left? My opinion is that the tilapia would do much better if they had lot of cover or a caged area of the pond to spawn and keep their numbers high enough to take care of the algae.
