I ordered some plants over a year ago (AquaticPlants.com), and they included a lotus bulb as a freebie. For several months it did nothing, perhaps because it was kept being rolled about by fish and current in the tank. Eventually it became somewhat anchored and developed some underwater leaves. Later it began to produce many larger and floating leaves, but at the same time the bulb itself was deteriorating possibly in part because the bushynose plecos like to chew on it.
With the bulb almost gone now, this plant has decided to bloom, rather spectacularly. I believe this may be its last gasp, but it decided to go into demise with a big 'splash'. Hopefully it will actually survive? Photos with the bulb and flower were taken 3 days apart. Clearly it has grown too large for its standard 125g tank, and it wants to continue to grow outside the tank. I cannot leave the tank open because of (very) jumpy Hemiodus fish.
Photos - 1) aspect of tank with underwater leaves (barely visible, left corner, reddish leaves among other plants towards the bottom), 2) emerging bulb (water level down during water change), 3) flower in full splendor, 4) flower today with lid closed. Cheers!