Such a sweet little boy. What species is he? Looks very similar to a dwarf or carpet chameleon 🥰 Glad he's ok. My cricket's food also get moldy at times, but I always replace it immediately. Luckily, my girl has also never gotten sick.
I use a medium to large bird cage covered in mesh for mine. The mesh is to prevent her from escaping from between the bars. I have branches and leaves in there and it's perfect for giving her safe outdoor time.
In the meantime while waiting for a fecal, you can give him Luke warm soaks in very shallow water. Don't take your eye off of him while he soaks and if he is comfortable, massage his side's or tummy in a downward motion. This helped my girl when she was constipated. Good luck!
Can you spot the chameleon? 😉 This is a wild newborn (most likely female) Bradypodium Ventrale (Eastern Cape dwarf chameleon) enjoying a bask in the warm South African sun.