Help with plant condition

[Gilamonster]

Hi guys,
Decided to revamp my tank before CNY and started to add some plants but need some help.
The plant seem to grow well but new leave are thin and long compare to the original condition brought.
Sorry for the bad pic. If you can see the bottom leave, they are rounded. On the top (new leave) are long and thin.

Tank is old and filter is with medium that have been running for some time.
I did a 80% water change before adding new soil, fish and plant.
Soil are new but cannot remember the brand name (Some Japanese brand similar to ADA I brought from NA / red package)
4 x T5 light on for 8 hours daily.
Have not started dosing any fertilizer. Is that a sign of malnutrition?

[Urban Aquaria]

The plant is called Rotala sp. 'Nanjenshan'.

The difference in leaf growth form that you are observing is normal... the bottom leaves are the emersed form (which are commonly sold as such at most LFS), the top thinner leaves are the adapted submersed form.

[Gilamonster]

Thanks for the info
relieve to know that they are doing ok.

Seem to prefer emerged form better tho

[Urban Aquaria]

If you are keen on similar plant species which maintain an oval leaf shape (not the thin spiky leaf shape), then can maybe consider getting Rotala rotundifolia or the Rotala sp. green variant, both still retain their original leaf shape in submersed form.

[Gilamonster]

Shall do some research on these, thanks.
Are these low requirement plants as well? Since I m still new, would try to keep to low requirement plant so that I don't "kill" them
So many plants out there to try

[Urban Aquaria]

Yeah, rotala species in general are relatively easy plants to grow, they are commonly used as fast growing stem plants for the background in an aquascape.

Do note that the older bottom leaves will eventually deteriorate over time, so you'll just need to trim the healthy top sections and replant them (discard the bottom sections) as part of regular plant maintenance.