20w Solar panel (SCA brand, has controller built in) $250 - $300 approx. Deepcycle (must be deep cycle, designed to discharge, unlike car batteries) battery 120 amp hour $300 approx. Power Inverter under $100. So, call it around $650-$700 start up cost. Depends on how much you spend a year for fish tank power to decide if it could be viable.
Any electricians out there that know how many amps a filter, air stone and heater would draw an hour, roughly?? Would 120 amp hour battery and 20watt charger cover it?