Read this before using the inch/gallon "rule"

[tpl*co]

what's worse is:

Recommendations I've read for tetras (larger ones, not just neons). They have a small minimum tank size, say 15-20 gallons, and then say get at least 6!

I wonder, if you do have good filtration since tetra's are highly community schooling fish, that you can put more in a tank as long as the water is kept up (and the fish have room to swim, LOL). I have 5 elreys and 6 yellow tail congos in my 46-48 gallon tank with my other fish, and they all move in unison! (they are completely happy. In fact when I had less they were more stressed and nervous and hid. Now I agree having a type of fish with an attitude and anti social behavior would probably be less fish in there.

 

[aquariumfishguy]

Originally posted by hcgirl80
I Always Heard That The 'Inch/gallon' Rule Was Only True till The fish got over 3'', Then It Got Different.

No, that is yet another modification to the myth. It has much more to do with the width of the fish, and the overall mass of the fish. For very slim bodied fish such as Neon’s or other Tetra species similar, the one inch per gallon "rule" usually works... provided you start with a 10-15 gallon aquarium.

However, it’s much safer to look up the individual specie than to assume they fall under a categorical placement of "___ inches per gallon", as it is usually much more complex than that.

 

[tpl*co]

What about disc shaped flatish type fish?

Mine are high bodied, but slim otherwise as volumes go. I wonder if the inch per gallon would apply?

 

[Faramir]

I'm not sure how relevant the metabolism of the fish is. The total ammonia produced can only equal the total nitrogen of the food you put in there. It doesn't really matter whether that nitrogen has been processed by a swordtail or an angelfish - or just by the rotting of uneaten food; neither can actually manufacture nitrogen atoms, so neither can actually "create" waste as if out of thin air.

I seem to find people quoting this rule a lot. I suppose it's nice and easy - but what's the point of being easy and wrong?

I disagree that it's the "neon tetra rule" - I suspect you could easily double or even treble it with neons. To my mind, it works for fish at about two inches. If they're normal fished shape. And they aren't aggressive. And they don't have special needs. And... and... and....

 

[jamzwayne]

Well, I personally wouldnt want too many fish in my tank. I like a calm, quiet, peaceful looking setting. Too many fish make the tank look "busy". To me, thats not peaceful. IMO

As far as the 'Inch/gallon' Rule....It doesnt make since to me, because you can only guess at the size your fish may grow.

When you start your tank with an Oscar in a 10 gallon all by himself, he will or should be fine until he grows up and becomes a big boy. - Am I right on this?

 

[roliva]

Some people say that if the fish is too big to turn around, then it's time to get a bigger tank, as in the 10 gallon situation. I however would not start an oscar in a 10 gallon tank, the growth rate is very fast and being confined to such a small space, the growth would be stunted before you even know it.

 

[jamzwayne]

I was using the Oscar in a 10 GAL as an example, but you know what I mean, right?

 

[OrionGirl]

Still not accurate. If you make frequent, large water changes on that 10, then yes, the oscar should grow sizable, without major problems--but will still need to be upgraded, and likely long before it's size hampers movement. The problem is that all growing fish produce hormones. These hormones work in many ways--in nature, they work to suppress the growth of other fish, minimizing the competetion for food. The largest, most successful fry produce more hormones than weaker fry--resulting in more food for the larger fish. In a tank, these hormones are still produced, but can't diffuse as easily as they do in a lake or river. The result--a single fish can produce enough hormone in a small tank to stunt it's own growth.

 

[mechanic]

The perfect example of why the inch/gallon rule dosen't work.
"You mean to tell me my 14" Oscar isn't doing fine in his 15 gallon tank?" :laugh:
later
E

 

[gonefishin]

I've heard the inch per gallon rule used as CUBIC inches of fish per gallon. We know that mass increses exponentially with an increase in length. that is to say (using a perfectly cubic fish) a 1"x1"x1" is 1" cubed an would need 1 gallon of water. a 2"x2"x2" fish would need 8 gallons of watter etc. I have a one gallon tank for feeders and i use the rule quite often for this. usually 10 small goldies or 30-40 guppies look like about 1 cubic inch and willl do fine in that tank. I think if we look at the rule again at its origin (which i've yet to find here) rather than its assumed meaning we will find it's more accurate than stated above. This is not to say the rule is law, it's a general estamate and of course some species are exempt(every rule was meant to be broken).