Looks like some variation of Hygrophila corymbosa... maybe Hygrophila corymbosa 'siamensis'? But i don't think it typically has the red coloration on the bottom sides of the leaves like yours does.
Or maybe it's some sort of Nesaea...
I honestly don't know, it could be some sort of ludwigia too.
Or maybe it's some sort of Nesaea...
I honestly don't know, it could be some sort of ludwigia too.