One pic is of one a clutch I bred in 2007 and the other is of the mother.
This outside cage has a large filtered pond about 6 x 4 x 1' The boxes are hide boxes filled with straw where they sleep and hide over winter. As I live in Brisbane, I don't add any heating.
Their diet is nearly entirely mice but there are also yabbies in the pond which the mertons will hunt for and catch. They have depleted the pond of goldfish which I buy and add once a year.
Young ones I keep inside in an old aquarium, heated with a small plastic container of water, big enough to swim in, small enough to lift out by hand and empty. Over winter, I use an aquarium heater to keep the water tepidly warm. The young ones are raised on bait fish and chopped chicken with calcium added. They will also eat a bit of beef heart but rarely show a lot of interest crickets though I have seen them eat one or two. The bait fish is their favourite.
I just put another clutch in the incubator 2 days ago of 13 eggs so hopefully will raise a few more at the end of the year.
The cage has worked really well but if I was going to build another I would leave more room in the sunny end because there isnt a lot of space for the female to burrow to lay eggs there. The other end is completely covered and rainproofed because thats the direction from where the storms blow hardest.
I think the pond is an essential part of keeping Mertons. If you can't give them good water to swim in, I don't think you should really be keeping them.