What plant is this?

[allthingslife42]

Just wondering what (hanging) plant this is? And how to look after it.
I have it in 2 tanks, one at 24C, one at 28C
The latter is turning brown in the photo yet the 24C is doing well

 

[Brookster123]

Leggy hornwort?

 

[Bert2oo1]

Liminophila sassifolia? Or milfoil? If it's not in high light then it's not milfoil