touch tank doesn't seem like a good idea. Any hands in the tank, especially those of little kiddos, is going to present problems:
That being said, a shallow tank for kids to LOOK down into is certainly feasible!
- You'll get all sorts of contaminants and potential toxins from hands into the tank, and with that relatively small water volume, that can cause problems including death of your livestock.
- If the kids happen to touch their eyes/mouth etc after "touching", this can also cause irritation and injury
- Some creatures may harm your kids' hands. Thinking crabs, bristleworms...
That being said, a shallow tank for kids to LOOK down into is certainly feasible!