Thank you for a much better picture! I believe that Solcielo lawrencia is correct in that you do have a deficiency.....most likely calcium.
I have grown that species for several years, it is a great plant in both larger and smaller tanks. Occasionally I will get a leaf similar to the one in the picture. Does it seem 'thicker' than an normal leaf and maybe the leaf is not as soft or flexible? When I have had it occur it is always a new leaf and it occurs as the leaf is 'unfolding'. When it first happened several years ago I didn't know what was causing it. I re-checked my water parameters and my dosing levels and researched and problem. What I found was:
I checked my water parameters and my dGH was down to about 2.0 (my water comes out of the tap and about dGH=1.0-2.0). I hadn't been dosing my GH Booster as conscientiously as I should. I increased my dGH slightly by adding GH booster which contains both calcium and magnesium and the problem disappeared.
As for the problem with the floaters it also seems worse on newer leaves. See if the problem improves when you start dosing GH Booster.
45 gallon tall (24" high) with Nymphoides hydrilla (sp 'Taiwan')