Leaderboard

Probably an easier option than an old bath tub (especially ensuring all chemicals that may have been used to clean it over the years are well and truly gone), and possibly safer stability wise, would be a 500L tub/ trough from Bunnings. I got one for my two dogs and it is sturdy and has straight sides and being round there are no corners for the yabby's to brace against to shimmy up the sides. The other bonus of the trough design that I got for my dogs is that the pond is above the ground and the sides are too high to allow cane toads in, where as cane toads have always still managed to get into the old bathtub I use as a pond.

See if you can source an old bathtub Will. They are good as they hold a lot of water and the sides are too slippery to get a purchase on so they shouldn't be able to climb out. If you use too small a tub the water gets way too hot. I have a shell clam - child's play pit type and a deeper plastic sand pit but in summer even under shade the temp in them has been at least 33 that I've measured and probably higher . The Cherries have survived for 3-4 years out there but I've now put the Taitibees in a bath and that seems much more stable. Good luck with her