Size matters
Many people use the excellent (but most of time far too slow) web site www.fishbase.org as a reference for their existing fish and future fish candidates. I think it is fantastic that people use scientific resources instead of most of the time idiotic hobby forum discussions but there are a couple of things you should be aware of when going through the data.
The first and most important thing is the published size (length) of the species. Pay great attention that www.fishbase.org publishes the maximum size recorded for each species! This is almost never the size 99.9% of fishes grows to. In addition, the size given is most of the time TL (total length) instead of more appropriate (for our application) SL (standard length); this means that the length given includes the tail portion of the fish.
Fortunately you can get the Standard Length and other interesting facts of the species by digging deeper through the data published. On the side panels I use Acanthurus achilles (www.fishbase.org/summary/SpeciesSummary.php?ID=4306) as an example.
Note also that unlike some self proclaimed hobby “experts” keep telling us, most fish species do not reach the same maximum size in home or public aquariums. Observations made in public aquariums show that the average expected maximum size is around 60-70% of published maximum SL (once again, note the difference in TL and SL). These fishes grew in a environment where neither food nor space was limiting factor.