Fish per Gallon?
- Thread starter joshob
- Start date
the inch per gallon myth has probably killed more fish than all diseases combined. the number and size of the fish you keep in your tank should be based on several factors. it should not be based solely on the chemistry of your water nor on the magic of the inch per gallon myth. it's more than simply a matter of successfully keeping the ammonia and nitrites at zero or the fact that you may have "great filtration". certainly these are important issues, but one of the most important factors is almost always overlooked. the number and size of fish that one maintains in a tank should be predicated on the "biology" and behaviour of those fish.
this means that the interraction of a mixed community tank and/or the behaviour of a single species is the single most important factor to consider. you want the fish you're keeping to have the ability to exhibit "normal" and functional behaviour. normal behaviour is important. abnormal behaviour results in stress. stress leads to disease. disease can lead to death. for example:
1. if species (A) does not get along with/is incompatible with species (B), then these fish don't belong in the same tank no matter how few fish you have or how large the tank. "getting along" is based on the visual and behavioural Q's that each fish species is genetically programmed with.
2. if species (A) has specific food or water chemistry requirements which are completely different from species (B), then these fish don't belong in the same tank no matter how large it is.
3. if species (A) is aggressive and defends a territory of 2 square feet, then you cannot expect to successfully keep more than one of these fish in a tank which is smaller than 2 square feet. convict cichlids are an excellent example of this ... this little fish aggressively defends territories of about two square feet give or take. if you have a tank which allows only that much room and no more, the convict will defend the entire tank to the detriment of any other fish (no matter how large it is) in that tank.
fish need room to swim without having the rest of the tanks inhabitants "in their face" continuously. when crowded, fish exhibit stress syndromes that result in poor color, improper fin form, insufficient metabolic development, do not exhibit proper musculature, do not develop properly functioning organ systems and most importantly slowly lose their inherant resistance to disease. this results in a significantly shortened lifespan and along the way, lots of diseases for which the poorly conditioned fish is a good target.
think about your local lake or river --- the fish are free to inhabit whatever space suits them biologically. if it gets crowded by their standards, some will disperse and move to other areas where they again have the space they need to exhibit functional behaviour.
it's difficult to allow for that "space" in your tank -- the fish have no escape within the confines of your tank so it's up to you to insure that the fish have that space in the first place. if your tank "looks bare" .. it's probably just right.
this means that the interraction of a mixed community tank and/or the behaviour of a single species is the single most important factor to consider. you want the fish you're keeping to have the ability to exhibit "normal" and functional behaviour. normal behaviour is important. abnormal behaviour results in stress. stress leads to disease. disease can lead to death. for example:
1. if species (A) does not get along with/is incompatible with species (B), then these fish don't belong in the same tank no matter how few fish you have or how large the tank. "getting along" is based on the visual and behavioural Q's that each fish species is genetically programmed with.
2. if species (A) has specific food or water chemistry requirements which are completely different from species (B), then these fish don't belong in the same tank no matter how large it is.
3. if species (A) is aggressive and defends a territory of 2 square feet, then you cannot expect to successfully keep more than one of these fish in a tank which is smaller than 2 square feet. convict cichlids are an excellent example of this ... this little fish aggressively defends territories of about two square feet give or take. if you have a tank which allows only that much room and no more, the convict will defend the entire tank to the detriment of any other fish (no matter how large it is) in that tank.
fish need room to swim without having the rest of the tanks inhabitants "in their face" continuously. when crowded, fish exhibit stress syndromes that result in poor color, improper fin form, insufficient metabolic development, do not exhibit proper musculature, do not develop properly functioning organ systems and most importantly slowly lose their inherant resistance to disease. this results in a significantly shortened lifespan and along the way, lots of diseases for which the poorly conditioned fish is a good target.
think about your local lake or river --- the fish are free to inhabit whatever space suits them biologically. if it gets crowded by their standards, some will disperse and move to other areas where they again have the space they need to exhibit functional behaviour.
it's difficult to allow for that "space" in your tank -- the fish have no escape within the confines of your tank so it's up to you to insure that the fish have that space in the first place. if your tank "looks bare" .. it's probably just right.
usually people go for that flawed 1 inch per gallon rule, but as people said already, it only can apply to small tropical fish (i think danios would appreciate a bit more space because of their hyperactiveness). and even then you'll have to know if its a schooling and shoaling fish or a loner like bettas.
I think it is pretty well established that the inch per gallon rule is bunk. As has been pointed out many times, this rule would allow a 10" Oscar in a 10g tank.
I heard a guy in the LFS tell a customer that he could do 1 fish per gallon. So, 10 Oscars in a 10g??? Nope. Bad rule. Can't do it.
Another problem is that even if a well-meaning beginner goes into the LFS and buys his inch of fish per gallon based on the max size of the fish as it is labelled in the store, he's probably still hosed. How often have you seen fish potential sizes that were grossly underestimated in the LFS?
The info provided at the point of sale is vague at best. What precisely does "Tropical Semi-Aggressive" mean anyway? Does this mean toward all other fish? Or just its own kind? There isn't room on the tag to tell you all of that.
Territory that a particular fish needs is very important. This has been covered. Another theory tries to go by how many grams of fish per gallon. That's a good one... So tell me, how much does a full grown {whatever species} weigh? That's not on the tag either.
Some fish are messier than others, and produce more waste. That has to be factored in.
Some fish simply shouldn't be attempted by beginners because they cannot tolerate mistakes.
Here's a rule that should be easier to live with, and may actually work. It comes in three parts.
1. Be patient.
2. Research fish you are interested in.
3. Before you buy anything, post your intentions in a forum like this one. You will benefit from (combined) countless years' worth of fish-keeping experience from people who have been there, done that. The advice is free for the asking, and the information is unbiased. The people here don't make a dime off you, so if the cheaper fish is the best move for you, they will not recommend an expensive one... And they will give you information that will help you keep fish alive and well - not keep you coming back to buy replacements.
I heard a guy in the LFS tell a customer that he could do 1 fish per gallon. So, 10 Oscars in a 10g??? Nope. Bad rule. Can't do it.
Another problem is that even if a well-meaning beginner goes into the LFS and buys his inch of fish per gallon based on the max size of the fish as it is labelled in the store, he's probably still hosed. How often have you seen fish potential sizes that were grossly underestimated in the LFS?
The info provided at the point of sale is vague at best. What precisely does "Tropical Semi-Aggressive" mean anyway? Does this mean toward all other fish? Or just its own kind? There isn't room on the tag to tell you all of that.
Territory that a particular fish needs is very important. This has been covered. Another theory tries to go by how many grams of fish per gallon. That's a good one... So tell me, how much does a full grown {whatever species} weigh? That's not on the tag either.
Some fish are messier than others, and produce more waste. That has to be factored in.
Some fish simply shouldn't be attempted by beginners because they cannot tolerate mistakes.
Here's a rule that should be easier to live with, and may actually work. It comes in three parts.
1. Be patient.
2. Research fish you are interested in.
3. Before you buy anything, post your intentions in a forum like this one. You will benefit from (combined) countless years' worth of fish-keeping experience from people who have been there, done that. The advice is free for the asking, and the information is unbiased. The people here don't make a dime off you, so if the cheaper fish is the best move for you, they will not recommend an expensive one... And they will give you information that will help you keep fish alive and well - not keep you coming back to buy replacements.