Well, I definitely disagree with the Fresh Coldwater Fish Information. You cannot keep 5 inches of goldfish in a 10 gallon tank...or 10 in a 20 gallon, etc. I do not think that you can make a fast rule about these things as, just as Butterfly said in another post it really depends more on the biological load of the fish. A pleco or catfish or scavenger of any size will put out more waste than many more freshwater fish of the same size. Bettas are pretty clean fish, but when I add Otos to the tank even though they are much smaller, the tank gets much heavier waste production than if I would be able to put 2 or 3 more Bettas in the tank.
I do not know if this is making a lot of sense, but the waste produced by the particular species of fish has to be taken into consideration and it will definitely cut down on the one inch per gallon "rule" if you have heavy waste producers. Probably if one were to have a tank of one species and that species was a fairly clean species of fish, you may get by using this chart for the Freshwater Tropical but under NO circumstances would I use the Freshwater Coldwater information and I know nothing about Marine tanks so I will not comment on the information about them.
Rose
