I have two established tiger lotuses. They have 5-8 large leaves and a good root system. Today when I was doing a gravel vac, I knock it around too much and the bulb came off. are these plants done for?
No, just keep the bulb in there and you'll get a third plant.
If the part that came off even has a bit of roots on it plant it. Unless it was just a leaf. I did the same thing with mine. Replanted the part that fell off and its growing just fine. But as for the bulb I agree with the above post. It will regrow too .