I've been seeing a lot of new members using this "rule" and handing out advice that may not be correct, so I'm going to list the reasons I know of why it isn't usually very accurate.
1. This one is pretty obvious, but I might as well say it. You can't put a 10" oscar in a 10 gallon tank, or two 5" gold gouramis either. The "inch per gallon rule" does not take into affect size of fish. And don't believe the other :bs: notion that a fish will grow to the size of it's tank. A fish will grow until stunting kicks in, and after that, it has little time to live.
2. You can't keep 10 tetras that belong to 10 species in a 10 gallon tank. The "inch per gallon rule" does not take into affect the needs of different species and sexes. Some fish need more space for territory. Some need schools. Some need a certain male/female ratio. Some need more swimming room than their small frame would suggest. Many get much bigger than their small frame would suggest, as well.
3. You have to think about the adult size of the fish. You can't keep 10 oscars in a 10g just because they're all an inch long. Oscars, for instance, can get 18" long, and 1 alone needs a tank 10x bigger than a 10 gallon. Many fish stores give 10 goldfish to new fishkeepers, giving them a shove down the hill that ends in wasted money and wasted fishy lives.
4. It doesn't take consideration the length of fish or large waste producers, like plecos. A 3" kuhli loach might make as much waste as a 2" dwarf gourami, but the "inch per gallon rule" doesn't include that. A 1" dwarf puffer can be as dirty as a school of 6 neons, but the "rule" doesn't both to mention that.
In the end, it is a sketchy rule of thumb that was made by people who didn't know enough to decide upon it. I wouldn't be surprised if it was made up by a LFS employee out there and was eventually treated as law. Think of it as this: There isn't a rule that 3 people in a living room will become friends. Why should there be a rule like for fish?
P.S: If anyone wants to add or comment (constructive critism only please), feel free to do so. Thanks,
-DP
1. This one is pretty obvious, but I might as well say it. You can't put a 10" oscar in a 10 gallon tank, or two 5" gold gouramis either. The "inch per gallon rule" does not take into affect size of fish. And don't believe the other :bs: notion that a fish will grow to the size of it's tank. A fish will grow until stunting kicks in, and after that, it has little time to live.
2. You can't keep 10 tetras that belong to 10 species in a 10 gallon tank. The "inch per gallon rule" does not take into affect the needs of different species and sexes. Some fish need more space for territory. Some need schools. Some need a certain male/female ratio. Some need more swimming room than their small frame would suggest. Many get much bigger than their small frame would suggest, as well.
3. You have to think about the adult size of the fish. You can't keep 10 oscars in a 10g just because they're all an inch long. Oscars, for instance, can get 18" long, and 1 alone needs a tank 10x bigger than a 10 gallon. Many fish stores give 10 goldfish to new fishkeepers, giving them a shove down the hill that ends in wasted money and wasted fishy lives.
4. It doesn't take consideration the length of fish or large waste producers, like plecos. A 3" kuhli loach might make as much waste as a 2" dwarf gourami, but the "inch per gallon rule" doesn't include that. A 1" dwarf puffer can be as dirty as a school of 6 neons, but the "rule" doesn't both to mention that.
In the end, it is a sketchy rule of thumb that was made by people who didn't know enough to decide upon it. I wouldn't be surprised if it was made up by a LFS employee out there and was eventually treated as law. Think of it as this: There isn't a rule that 3 people in a living room will become friends. Why should there be a rule like for fish?
P.S: If anyone wants to add or comment (constructive critism only please), feel free to do so. Thanks,
-DP
Bob was only disagreeing politely to Guppy's post in MFK.:grinyes: