Its actually water...what would be part of their elimination of urates.. Many lizards and snakes will bathroom when handled a bit too roughly or in a way that frightens them....its a defense mechanism.. often times its enough to make a predator drop them. Its nothing to worry about at all.. the clear liquid with a thin consistancy actually is good. It means your gecko is very well hydrated and can afford to waste the water. Being a desert animal they'd be built to conserve water at all costs when its needed.
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Lucien
1.1 Columbian Redtail Boa (BCI)(Sutekh and Isis)
2.1.1 Leopard geckos (2 Blizzards (Caine and Goliath), 1 Tangerine Albino (Tequila Sunrise ...Tiki for short) and 1 dbl. het blizzard x tang albino (Malice))
0.1 Savannah Monitor (Kiros)
13 rats
1 Gerbil
2 Dogs (Loki and Storm)
2 cats (Sahara and Hercules)