One of my brother's aquariums is infected with Planaria worms, so I did an experiment, when I transferred a bit of the plants to a 15 gallon tank, the new tank eventually got infected with lots of worms... so I put in a few strands of aldrovanda to see if the Aldros will eat them, I didn't think the worms will eat my plants.
After a day, the worm numbers reduced a bit, after 2 days, only big ones can be seen, after 3 days, almost no more worms.
Top view, showing that most of the traps have brown/white stuff in it, those are the worms. Little bit blurred but you can see them. There is also a photo of a planaria worm in the middle of the photo, not sure if it was half caught or not.
Underwater view of some of the traps with their prey.
When disturbed, the worms would actually make themselves shorter,which means even the biggish ones will fit the trap, but I have witnessed a few times when a worm is halfway in only, in which case the worm usually is able to get away. Planaria worms if cut into two will end up becoming 2 worms.
Lessons learned?
1. Aldros are vicious as VFTs in terms of catching prey, yes I think a few times I have seen them with mosquito larvaes in their traps.
2. Aldros can eat quite a lot of small stuff and will surely out eat Utricularia in terms of prey size. Water boatmen beetles, planaria worms, Mossie larvaes and as I reported before small/baby snails are all prey items.
3. I am pretty sure they will be able to catch newly hatched small egglaying fish fry. I am not sure about guppy fries though.