The characins are a large group of freshwater fishes found in South and Central America and Africa. They are characterized by the Weberian Apparatus (the linkage of bones between the swimbladder and the inner ear) that allows them to hear high frequency sounds.
These plants are not renowned for their flowers, but they give the pond a more natural feel and are important for the well-being of the fish. They spread to form a dense mass, protecting the fish from predators, especially birds, and also from sunburn, in addition to curbing algal growth. Furthermore, they provide spawning sites and food for some species of fish. Floating plants are easy to establish—simply let them drift on the surface until they find a suitable position—and they develop much faster in a new pond than other types of plants, such as marginals and water lilies. Some popular varieties originate from warm climates and are not hardy in temperate areas. They should be brought inside to protect them from winter frosts.
Floating plants are chosen less for their appearance than those growing in the main body of the tank and more for their function. They provide spawning sites and food for many fish species and also give cover and help to diffuse harsh aquarium lighting.
Despite their reputation for being difficult, it is possible to keep some killifishes in a community aquarium, and here three species spring readily to mind: Aplocheilus lineatus (Sparkling panchax) Pachypanchax playfairi (Playfair’s panchax), and Oryzias latipes (rice fish or medaka). These are surfacedwelling species, so they make a useful addition to the aquarium in that they occupy an area of the tank that is usually ignored when buying fishes.
