Water dish
Keep a clean water dish available to Goliath Birdeaters once the spider is large enough to use one safely. Place it where it can be removed and refilled without dismantling the main retreat.
If a Goliath Birdeater fills the dish with substrate or webbing, clean it and refill it. That behaviour is common and is not a reason to remove the dish permanently.
Substrate moisture
For Theraphosa blondi, use moisture-retentive substrate with very good ventilation. Never swampy and never allowed to dry completely. Judge the substrate over several days instead of trying to keep every part equally wet.
Add water in controlled amounts for Goliath Birdeaters. The lower layers can remain moist longer than the surface, especially in deep or fossorial setups.
Ventilation
Moisture without enough airflow can leave a Theraphosa blondi enclosure stale and persistently wet. Cross-ventilation helps moisture move through the enclosure instead of collecting as constant condensation.
If a Goliath Birdeater enclosure smells sour, remains soaked or repeatedly grows mould across the surface, reduce water, improve airflow or both.
Slings and small enclosures
Small Goliath Birdeaters enclosures dry faster because they contain less substrate and air volume. Check them more frequently without turning that into constant disturbance.
For a tiny Theraphosa blondi sling, use a suitably shallow water source when practical and keep the substrate appropriate for the species and life stage.
Around moulting
Keep water available when Theraphosa blondi is in premoult and after the moult. Do not disturb the spider to make it drink; simply make sure access is there.
After a Goliath Birdeater moults, leave the spider to harden. Hydration support means stable water access and suitable enclosure moisture, not spraying the animal directly.
Avoiding overwatering
More water is not automatically safer for Theraphosa blondi. Persistently saturated substrate can create poor conditions even for species that appreciate a moisture reserve.
With Goliath Birdeaters, aim for the moisture pattern the species needs while still allowing ventilation and some normal drying. The water dish remains the constant source while substrate moisture is adjusted as required.