Nymphaea water lily, maybe nymphaea stellata or rubra. It is normal for leaves to reach the surface, especially in lower light.
I concur, this is a Nymphaea, species might be N. lotus which comes in a green-leaf (dark olive green) and a red-leaf (often brownish-red upperside, pinkish underside) variant. I have the red leaf in my 90g. I will copy over a profile of this species I wrote a couple years back that may provide you some data on culture. As for the aponogeton, yes, the leaves of species are very long and will grow to the surface and then continue along the surface, sometimes for 2+ feet, depending upon species.
Common Name: Tiger Lotus, Red Tiger Lotus, Green Tiger Lotus
Origin and Habitat: Tropical regions of Africa and Madagascar [see additional comments under Description]. The red and green cultivars are natural; the red cultivar is found in shallow, standing water such as temporary pools and small permanent lakes. The green cultivar has been found in flowing waters.
Ideal position in aquarium
The roots must be in the substrate, and leaves will form submersed and floating. Floating leaves can eventually be suppressed by continually removing the larger leaves. Flowers, which are very rare in aquaria, will only form after the plant has developed many floating leaves; flowers open only during the night.
Moderate to bright. The red variety requires slightly brighter light than the green cultivar.
Minimum Tank Suggestion
25 gallon. Best in tanks no less than 16-18 inches in depth.
Water parameters for Tiger Lotus
Suitable for soft or hard water, it prefers soft, slightly acidic water. Optimum temperature 22-28C/71-82F.
The tiger lotus has a green-leaf and a red-leaf form, known as the Green cultivar and Red cultivar respectively, and these are naturally occurring. Some sources give Nymphaea zenkeri as the name for the Green "species" but this is inaccurate.
Both the red and green cultivars have the same requirements in the aquarium, though the red will have brighter coloured leaves in stronger light.
This species grows well in a plain sand or fine gravel substrate. With an enriched substrate, the plant will produce more leaves and have stronger growth. Flowering may occur with good nutrition and brighter light, provided the floating leaves are allowed to form. These can easily cover the surface, shading the lower plants. The flowers only open at night (during darkness).
The Nymphaea is a family of freshwater aquatic flowering plants commonly called "Water Lilies" and found in tropical and temperate regions throughout the world. There are eight genera with some 70 species; all are rooted in the substrate with leaves and flowers that float on the surface. The family was described by the British botanist Richard Anthony Salisbury (1761-1829). The name comes from the Greek for a "nymph" who was a goddess associated with waterfalls and springs. In spite of the common name, this family is not closely related to the true lilies, Liliaceae; the common name "lily" is applied to many variable plants.
The genus Nymphaea was established by Carl Linnaeus (1707-1758), the Swedish botanist, physician and zoologist whose monumental classification of all living organisms led directly to the binomial nomenclature system used today. There are about 50 species in the genus which is closely related to the Nuphar, another genus with aquarium species. Both are commonly referred to as "lotus" and in both the leaf is deeply notched at the base. The Nymphaea have a tuberous rhizome, though it is often absent in aquarium plants.
Nymphaea lotus was described in 1753 by Linnaeus. The species epithet is a Greek plant name. This species is widespread in tropical Africa and Madagascar, and was introduced to Europe. It is also now found wild in parts of North, Central and South America. Some sources also consider it native to SE Asia, but this is actually a distinct genus [Kasselmann, 2003]. This is a polymorphic species, meaning that there are external differences between some of the various geographical populations; further study may or may not determine distinct species.
Kasselmann, Christel (2003), Aquarium Plants, English translation, Krieger Publishing company.
Byron Hosking, BMus, MA
Vancouver, BC, Canada
Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]
Eek - why has Byron been banned?