The holes look more like mechanical damage.Is this more likely to be mechanical damage
Where is that video, with the dramatic music and amano shrimp eating plants?? Can't find it back, but it is posted in a simular topic about holes in plants as obviously as yours, mechanical damage.. But it's hilarious.. Not Amono's eating plants, nor holes in plants, but that video is. It made me want to cry a little.
Life-time of the individual leaf of Apon. ulvaceus is really not very long. Leaves are very delicate, too, making them unusually vulnerable to mechanical damages and all kinds of attacks, be it fungal, bacterial or from shrimp and fish. The plant makes up for this, by its unbelievable fast production of new leaves constantly.....given adecuate conditions.
Adecuate conditions for this plant is good light, very plentyfull fertilisation (root tabs are really benefitial here) and..........space !!!!
It's by nature a HUGE plant, and will tolerate "restrictions" poorly. It can be done - but it's on cost of general health of the plant.
Haha, t'was the music ... science fiction linked it here
http://www.ukaps.org/forum/threads/leaves-nymphoides-hydrophylla-taiwan-almost-gone-overnight.40456/
It is an easy Aponogeton (most Aponogetons are), but it still is a very hungry plant. All this growth comes at a price, so to speak.
If you can afford it, it really will benefit a lot from being allowed an extra ratio of nutrients at its roots every 3 or 4 month.