There are many different methods to try to standardize advice for marine aquariums, but in reality, there is so much different from tank to tank that any advice would be taken with a grain of salt (pun intended). Case in point, the age old “one inch per gallon” rule. On the surface, it’s nice to have a standardized method for adding fish to your aquarium. How much is too much? How many fish can or should you have? Well, the problem with the “inch per gallon” is that it just doesn’t make sense in virtually every situation. Would you put fifty two-inch fish into a 100-gallon aquarium? Absolutely not. What about a handful of 6 inch fish for a 30-gallon nano aquarium? It’s very obvious that rules like these don’t fit at all and should be avoided at all costs. Instead, all advice should be tailored specifically for each situation. Take things like aquarium size, filtration equipment, and adult fish sizes into consideration as well.