Are you going for a certain look, or do you basically just want light and heat ? They make very inexpensive heaters for small tanks. I think my Tetra 2-10 gallon heater cost around $7 USD. Chances are the manufacturer of your tank makes a light / hood that fits perfectly. A clamp on type fixture and a clear cover would be another option. In any event, I think a separate heating unit would be best. Hope this helps.