Quit feeding your BTA. Let it eat what it can snag from the feeding of the rest of the tank. I've never, ever, ever fed mine anything that wasn't going to the rest of the tank. I've had something over 25 clones over the years. They are primarily photosynthetic. When you target feed them like feeding them silversides - UGH), most of what you feed them just gets dumped back into your tank as waste.