[I've read that if you want to look at your tank at night without disturbing the nocturnal inhabitants that you put a red lens/filter over your flashlight.
1 - is this correct
2 - if the answer to one is yes, where can I find a red lens/filter]
[That is correct. And if you will go to army/navy surplus store they sell those little flashlights with the light at a 90 degree angle that have red filters that come with them.]