I'd actually guess that it was C. moehlmannii since the undersides of the leaves are the same green as the tops. C. pontederiifolia grown in bright light typically has a pink to violet underside. I'm guessing on the bright light based on the size of the plant pictured.
"Marsh plant with a creeping rhizome, 10-30 cm tall. Leaves 5-15(-20) cm long petiolate. Blade lanceolate to narrow ovate, 10-15 cm long and 3.5-7 cm wide, smooth or slightly bullate. Apex acute and base slightly to distinctly cordate. Margin entire. Light to olive green coloration, not brownish.
Spathe 4-6 cm long. Tube 0.5-1 cm long. Limb 3-3.5 cm long, cuspidate, more or less erect (form from Tapaktuan) or 1-2 times obliquely twisted (form from Sasok), mamillate, interior dark purple-red. Collar narrow. Throat and collar colored similarly to the limb. Female flowers 5. Male flowers 25-30. Number of chromosomes 2n = 30."
"Marsh plant, 10-40 cm tall. Blade lanceolate to narrow ovoid, 9-14 cm long, 3-8 cm wide, smooth or slightly bullate, light to olive green, occasionally brownish or mild violet. Apex acute; base usually cordate.
Spathe 4-7 cm long. Tube up to 0.5 cm long. Limb 1.5-5 cm, cuspidate, erect or recurved, little twisted, rough to slightly wrinkly, interior yellow or reddish. Collar wide, smooth to a little rough, coloring like the limb. Female flowers 5-6. Male flowers 20-35. Number of chromosomes 2n = 30."