I do not own a marine aquarium i am just curious! Are marine fish expensive (in comparison to your regular FW fish) because they are all wild caught? Or are they hard to breed?
Nope, i guess it depends on availabilty. You can pick up some damsel for like £4 from the LFS and clowns are under £10. Obviously the rarer they are the more cost they run up the same as FW fish i guess?
Supply and demand... Most FW fish are tank-bred and as such are much cheaper. Tank-bred SW fish are also cheaper, but still in limited supply because of the fewer number of hobbyists. Most SW fish though are wild caught and that of course leads to a very limited supply. When supply is low, price goes up, simple as that . And when supply is low and demand is high (think flame angelfish) the price goes WAY up.