Yellow-Bellied Slider — care sheet

Intermediate. Not hard to keep alive, but genuinely hard to keep WELL. The commitment is the real difficulty: a hatchling the size of a cookie grows into a dinner-plate turtle that needs a 100+ gallon setup, powerful filtration, real UVB, and 40+ years of your life. Get the big-picture husbandry right and the day-to-day is forgiving.

Omnivore with a lifelong shift: hatchlings and juveniles are mostly carnivorous (insects, worms, small fish, crustaceans), while adults become predominantly plant-eating. Base the captive diet on a quality aquatic-turtle pellet plus lots of leafy greens and aquatic plants, with protein (feeder insects, earthworms, occasional fish) a smaller share for adults. Feed juveniles daily; adults a portion every 2–3 days.

Minimum 100 US gallons (about 379 L) of water for a single adult, using the standard 10 gallons of water per inch of shell length rule. A 120-gallon tank (roughly 48" x 24" x 25") is a more realistic, widely available target and is what most keepers should aim for. Bigger is always better; stock tanks and large Waterland-style tubs are excellent alternatives to glass aquariums.

Adults: 70–88°F (21–31°C). Juveniles run a bit warmer (around 74–76°F) and hatchlings warmer still (about 78–82°F / 24–29°C). Use an aquarium heater rated for your full water volume, guarded so the turtle can't crack or burn against it.

At least as deep as the turtle's shell is long, and preferably deeper. These are strong, active swimmers that dive and forage, so give them a genuine water column, not a puddle, as long as they can always reach the basking dock and the surface easily.

Turtles are messy, so oversize your filter: a canister filter rated for at least 2–3x your actual water volume is the working standard (many keepers go 3–4x). For a ~100–120 gallon tank that means a canister rated in the 300–400+ gallon range. Even with strong filtration, do a partial water change of roughly 30% every 1–2 weeks and clean the filter monthly.

A large, sturdy DRY dock or platform (big enough for the whole turtle to climb fully out and dry off) positioned under the heat lamp, with a basking surface temperature of about 104°F (40°C). Air temperature just above the basking spot should sit around 85–90°F (30–32°C). An easy climb-out ramp is essential.

Lights and heat lamp off at night is fine, and the basking area can cool to room temperature. Many keepers turn the water heater off overnight and back on in the morning for adults; keep hatchlings on consistent warmth instead. Don't let the room get cold-drafty.

A linear T5 HO UVB tube is the standard, such as a Zoo Med Reptisun 5.0 (T5 HO) or Arcadia Forest 6% (T5 HO). Yellow-bellied/pond sliders fall in Ferguson Zone 3; aim for a UV Index of 3.0–4.0 on the basking surface. Mount a 5.0/6% bulb about 11–13" (28–33 cm) above the basking spot (further for stronger 10.0/12% bulbs), never closer than 10". The bulb should span 50–75% of the tank length. Replace T5 HO tubes about every 12 months, and run lights 11–13 hours/day (shorter in winter, longer in summer).

Bare-bottom is the easiest and cleanest option for an adult tank and makes water changes simple. If you want a naturalistic look, large smooth river stones (too big to swallow) or a play-sand shoreline area work; avoid small gravel, which turtles can ingest.

Even with good UVB, dust food with a calcium supplement (calcium carbonate, no phosphorus) regularly, and offer a cuttlebone floated in the tank for free-choice calcium. A vitamin/D3 supplement can be used sparingly, especially indoors, but real UVB is the primary way sliders make vitamin D3, so it is not a substitute for a good bulb.

Males roughly 5–9 in (13–23 cm) shell length; females larger at 8–13 in (20–33 cm). Most captive adults settle around 8–11 in. Females are noticeably bigger and heavier than males, so plan your tank for a large female even if you buy a hatchling.

Up to ~30 years in the wild and 40+ in good captive care — a multi-decade commitment, not a starter pet.

See a reptile or exotics vet if you notice: Soft, spongy, or misshapen shell, twitching, weak limbs, or fractures, classic metabolic bone disease from poor UVB/calcium. See an exotics vet.; Bubbles or mucus from the nose, wheezing, open-mouth breathing, listing/swimming lopsided, or a sudden loss of appetite, possible respiratory infection. See a vet promptly.; Swollen or crusted-shut eyes, often a sign of hypovitaminosis A or infection, needs a vet.; Pitting, sores, foul smell, discoloration, or lifting/shedding scutes on the shell, possible shell rot/infection, which can become life-threatening.; A female straining, restless, digging, then going off food and becoming lethargic, possible egg binding, an emergency.; Any prolapsed/protruding tissue from the vent or tail, treat as an emergency and see a vet immediately.; Persistent not-basking, floating abnormally, lethargy, or refusing food for an extended period, general 'something's wrong,' get a check-up rather than waiting..