Trachemys scripta

Aquaterrarium or large pond: a substantial water volume allowing free swimming + an accessible dry basking platform. An outdoor pond (temperate climate) is ideal for adults.

Minimum for ONE adult female; the usual rule: tank length >= 4-5x the carapace, water depth >= 2x the carapace height so she can swim and right herself. LEGAL WARNING: Trachemys scripta (notably elegans) is classified as an Invasive Alien Species of Union concern for the European Union (EU Regulation 1143/2014): sale, exchange, breeding and release are BANNED in the EU. NEVER release into the wild. Keeping animals acquired beforehand may be tolerated under certain conditions depending on the Member State — check local regulations.

Not a limiting parameter for an aquatic species: ambient humidity is managed by the body of water. Water quality and temperature matter far more than air humidity.

Absolutely rule out small gravel and glass beads: swallowed during feeding, they cause digestive blockages. A bare bottom makes cleaning and monitoring water quality easier.

Essential. UVB strip/tube 5.0 to 10.0 (T5 HO 6-10 %) above the basking platform, replaced every 6-12 months. Photoperiod of 10-12 h. Without effective UVB (combined with calcium), the animal quickly develops osteodystrophy (MBD) and a deformed shell.

Water quality is critical: powerful filtration (flow rate >= 2-3x the tank volume/hour, external filter recommended), dechlorinated water, regular partial changes. Depth sufficient to swim and submerge fully, while still being able to surface to breathe and right itself. Cold or fouled water is the leading cause of illness (respiratory, skin, eye).

North America: central and southeastern United States (Mississippi Valley) to northeastern Mexico. A widely introduced species that has become invasive on every continent.

Shifting omnivore: carnivorous juveniles, mostly herbivorous adults — Young: small whole fish (not to excess), earthworms, aquatic insects, quality aquatic pellets. Adults: aquatic plants (elodea, duckweed, water lettuce), leafy vegetables (endive, dandelion, watercress) supplemented with occasional protein.

Feed juveniles daily, adults only 2-3 times/week (obesity and shell pyramiding are common in captivity). Provide a cuttlebone (calcium) at all times. Avoid excess animal protein in adults. Do not give mammal meat or bread.

Clutch 6–25 eggs/young. Provide a terrestrial nesting area (a tray of moist, loose sand/topsoil) accessible to gravid females; otherwise there is a risk of egg retention (dystocia). Incubation ~55-80 days at 25-30°C. Temperature-dependent sex determination (TSD): low temperatures -> males, high -> females. Reminder: breeding this species is banned in the EU (Reg. 1143/2014).

• Osteodystrophy / MBD and shell pyramiding (UVB or calcium deficiency, or excess protein)
• Hypovitaminosis A (eyelid swelling, oral plaques, ocular discharge)
• Aural abscesses (ear infections) — often linked to hypovitaminosis A and poor water quality
• Shell rot / skin ulcers (shell rot, fouled water)
• Respiratory infections / pneumonia (water or air too cold)