[ValorG]

Whether you need a heater depends on the type of shrimp and your room temp. And I would say yes you need a filter unless your willing to do small water changes everyday to every other day with aged water, which in any case youll need an airstone anyway. The water should not be stagnant.

 

[ValorG]

You can place the bowl in a partially filled heated tank/shallow container with some sort of platform underneath. As long as an inch of the bottom of the bowl is under water, it will warm it well enough.