I think I had it in a 20g long, medium light...& of course lame ferts of any kind (sigh). I don't remember holes in the leaves or it turning yellow, that may be different issues. Mine just didn't look good for too long & I may have ripped it out accidentally or in a fit of frustration, or for new plants to try. I do think better ferts would help a lot as dougall & Noodle said.
What kind of lighting have you got Hexo? On my 75g I have 2 T-5s (HOs? I don't recall), I'd call it medium-ish. I tried Brazilian pennywort (h. leucocephala) a long time ago in it. As I recall it's leaves seemed larger & darker green than Noodle's look, at least for a while...mine was in the substrate.
Flourish root tabs are mainly micros, not much at all in the way of macros (NPK). Maybe Hexo, yours needs more macro ferts, I'd think that could account for yellowy leaves...but not the holes so much...I don't know what that means.
Do you have a test kit to tell your nitrate level? It's the N of NPK. Phosphorus (P for potash in NPK) is often from fish food & waste. In a lightly fed tank that could be low but not too likely is my understanding...K is for potassium. I think there's a sticky at the top of this plants forum that explains ferts better than I can...Well, I kind of know, I just don't dose them...You & I Hexo both need to up our fertilizing game!