If there isn't any ceratophyllum or similar vegetation available then eggs are scattered out on rocky bottoms in still water.

Ceratophyllum dersum grows in still or very slow-moving water.

Of these, 'Ceratophyllum demersum' is widespread, with a global distribution; the others all have more restricted ranges.

It provides dense plant matter (especially Ceratophyllum) for cover against predators and as a laying area of snail eggs.

Eggs are laid on ceratophyllum if it is available as it is in most wetland areas.

Ceratophyllum grows completely submerged, usually, though not always, floating on the surface, and does not tolerate drought.

Ceratophyllum echinatum is an aquatic herb.

Ceratophyllum muricatum Cham.

The name Hornwort also refers to aquatic plants of the genus Ceratophyllum, in the family Ceratophyllaceae.

Ceratophyllum demersum (N)

Podostemum ceratophyllum (N)

Ceratophyllum demersum grows in lakes, ponds, and quiet streams with summer water temperatures of 15-30 C and a rich nutrient status.

Ceratophyllum submersum (soft hornwort) is a species of Ceratophyllum.

Still in deeper water an association of manel Nymphaea stellata and the submerged aquatic plant Ceratophyllum demersum present.

Analysis of the lake has also revealed the tendency for it to develop monospecific communities of submerged macrophytes such as Ceratophyllum and Myriophyllum.

A. splendens will breed quite readily in the aquarium; some floating plants such as Ceratopteris or Ceratophyllum will provide protection for young fry.

Ceratophyllum demersum L. (Rigid Hornwort or Common Hornwort)

Ceratophyllum echinatum A.Gray (Spineless Hornwort)

Ceratophyllum submersum L. (Soft Hornwort or Tropical Hornwort)

This is suitable for growth of rooted submerged species such as Myriophyllum, Vallisneria, Elodea, Hydrilla, and Ceratophyllum.

Ceratophyllum echinatum, commonly called Spineless Hornwort, is an aquatic perennial plant of the family Ceratophyllum.

Ceratophyllum demersum (hornwort, rigid hornwort, coontail, or coon's tail) is a species of Ceratophyllum.

The larvae feed on Nymphaea alba, Potamogeton, Callitriche, Ceratophyllum demersum, Elodea canadensis, Nuphar lutea and Stratiotes.

Dominating aquatic macrophytes: Potamogeton welwitschii + Ceratophyllum demersum (submerged); Eliocharis dulcis, Oryza barthii, Vossia cuspidata, etc. (Ojda 1994)

However, a study in 2007 estimated that the division of the five most recent (the genus Ceratophyllum, the family Chloranthaceae, the eudicots, the magnoliids, and the monocots) of the eight main groups occurred around 140 million years ago.