A red-eared terrapin.

Aquatic and semi-aquatic turtles are popular as pets. The most well known is probably the red eared slider, although there are several other species which are kept as pets.
Size and Life Span.
Many people also do not realize how big aquatic turtles can get. Red eared sliders and a couple of the other commonly available pet species will grow to at least 10-12 inches long and thus will require correspondingly large enclosures. All turtles have the potential to enjoy a very long life span (i.e. several decades!) if cared for properly.

Housing.
Aquatic turtles require fairly elaborate housing. They need regular exposure to ultraviolet (UV) light, so pricey bulbs designed for reptiles that produce UVA and UVB light are needed for turtle tanks. Without this light, metabolic bone disease (soft shell syndrome) can result.
Turtles are messy, and a good filtration unit will be necessary to help maintain water quality, as will regular cleaning. They should have deep enough water to allow swimming, along with a place to get out of the water to bask (heated from above with a basking light.) In
addition, appropriate water and ambient temperatures should be maintained.

Feeding.
Although turtle foods have come a long way they are not recommended as a sole source of food for aquatic turtles. Most are omnivores (and preferences for different foods might change at different points in the life cycle), and offering a good variety of foods is the best way to feed most turtles. As a rule, feeding turtles in a separate plastic tub will allow the mess associated with feeding to be contained (turtles are messy eaters, and this will reduce the need for tank cleaning a bit) and allow monitoring of food intake of each turtle if multiple turtles are kept.

Thank You For Wasting Your Time Here to get some Great notes...