Hi just wondering how people have like 2-4 bulbs in 1 tank, considering would that not mean that you would need 4 lighting units and 4 plug sockets? or is there some thing that a lot of lights can plug in to???.
if the lights are designed to run off of straight wall AC voltage then running them in parallel is the way to do it. different bulbs and types have different ways you can wire them. most flourescent bulbs must be wired along with some circuitry ballast which is part of the bulb fixture. incandescents on the other hand are usually designed to accept straight 110V AC (if you're US/canadian, 220V if european).
wiring incandescents in series (one after the other) will make each successive bulb dimmer than the first as you go along the chain... not reccomended. instead you need to wire them in parallel by breaking off the hot and the ground wires at the same point. if using flourescents you have to wire the fixtures in parallel (series wont even give them the neessary voltage to start up).
if you're going for a homemade setup for lighting, please please please be very careful as you can really hurt yourself when playing with live AC voltage (110 or 220). make sure any an all connections you make are secure and insulated to keep everyone safe and try and use products designed for electrical work. above all else, if you dont know what you're doing, ask someone so that you're sure you're safe