Excellent information, this site is paying off in just one short evening as I was almost going to splurge £20 - £30 on one of those lights with air pump things.
Just got the cold cathodes off ebay for a fiver and have an adjustable power adapter just sat here on the side.
I added 4 blue LEDs as moon lights. It took me about 10 minutes with a soldering iron, lighter, speaker cable, heat shrink tubing and a sharp knife (I misplaced my wire cutters).
The heat shrink was glue lined, so made the finished item water proof.
The LEDs illuminate the bubbles from the air curtain at the back of the tank during the daytime.
I tried some 'ocean green' LEDs on the goldfish tank, but soon removed them
I had a bad experience with the cold cathodes. The inverters output a high voltage, when one cable was pulled out accidentally the pins arched and smoke bellowed out. I still use some cold cathodes, but I never leave them on if I'm going out.
Voltage isn't the concern, it's amperage. Most stun guns output 20,000 volts, but only about 3 mA so there is almost always no real damage done. The question is how much current would be coming out of those inverters.
10 mA is enough to kill if it goes through the heart. GFI circuits are set to trip at 5 mA I believe, so a GFI can literally save a person's life. 100 mA is lethal. The walls of your heart flutter and you die. At 200 mA the current is so strong that the heart doesn't flutter, it just clamps up, giving you a better chance of survival.
use some aryldite or silicone sealent. then put the hood back on and leave to dry. (while drying get some electrical tape to secure it so the neon doesnt come away from the glue) then when dry remove the tape. bingo.