In keeping reef/FOWLR tanks responsibly, one of our tasks is to be sure that the animals in our care are provided with an adequate habitat to live in. The "tang police" have a bad rap, but that really is their goal (usually...I think anyway...). I mean, let's face it, the ocean is huge, so even public aquariums with their tanks of multiple thousands of gallons pale in comparison to the natural habitat these animals are taken from. Still, it doesn't make sense to say that no tank is big enough (after all, our other pets do fine...and their natural habitat is equally large). So, there has to be a reasonable way to make a determination about size requirements, right? However, there are a lot of different ideas on this and a lot of places to go for info. Some people use "rules" or principles to determine the "correct size" for their fish/tank ratios (the inch/gallon rule comes to mind...but I hope we've abandoned that one by now...). Others use websites or charts that they trust are based on data collected by the "experts." These reefers recognize that they themselves have not done the research (nor could they) personally, so they're relying on those they assume have done it for them. ...and the cool thing is that apparently these methods are working because we see healthy (dare I say "happy") fish in reef tanks living for years under the care of their owners. Man I love following Brad's reef! All of the inhabitants are thriving (including some difficult to keep fish that many of us would hesitate to try). So, here's the question for discussion. What have you found to be a good way to determine appropriate size requirements for different types of fish. What is your go to source (or do you have one)? What would you recommend to a new reefer who is just getting started and trying to decide how to determine what they can put in their tank? If the answer is "do your research" where do you suggest they start? What has worked for you?