Decided to go with extra volume. Got a 6 x 2.5 x 2.5 so I can put some small motoro rays in it. Any advice for a first time ray keeper? I know amnomia has to be none at all. Also they eat a lot. Heater can't be in tank Correct? What's best setup for filter and heater wise? How do I setup heater and all? Thanks. Any advice appreciated.