The "one inch per gallon" rule

[SimonL]

Addikted, your sarcasm detector needs new batteries

I was just joking, as the rule works rather well for small fish, but goes out the window with monsters. Maybe something like one cubic inch of fish per gallon lol.

 

[Addikted2Cichlids]

lol.. U never know.. I'll have to get them replaced haha.. Yeah I agree with the monster part thats why I said it works well for the most part..

 

[gtclipse01]

For small fish like glo-light tetras you will end up with something like this, 1 1/2"x 1/4"x1/2", this comes to 3/16 of a gallon (about 1/5), and that gives you 5 fish of this size per gallon (quite reasonable)

I think the cubic inch rule works better for larger fish, but for smaller ones I think the length may be a better guideline. Somehow I don't see the average 10 gallon tank being able to handle the bioload of 50 neon tetras.. you'd need a crucial wet/dry like an LFS for that to work.. and even then they'd be so cramped and stressed over a long period of time that they'd be very likely to wipe out from some disease.

Using the length rule for small fish would come up with about 7 1.5" tetras to a 10 gallon, which might be a little on the underside, but I'd say it's much safer than 50. If a fish has any dimension under 1" and their length is under 2" or so, it messes the cubic inch formula up IMHO.

 

[skyhigh]

for some reason i dont think it sould be LxWxH because if a fish is 5" X .5" X 2.5" its only 6.25 gallons that doesnt seem right.... You could keep that one fish in a 5 Gallon almost... I dont get it...

 

[Reyairia]

I think the "one inch per gallon" only really applies to beginners who only keep livebearers, tetras and bettas. In which case it works out pretty well, once you get to larger fish things get quite different.

 

[knifegill]

So 5 x .5 x 2.5 would be like a farlowella or needlefish, right? If so, 6.25 would work for the bioload, but not for the fish itself, I'd think. If it were a fish shaped like a seahorse (freshwater pipefish maybe) then, yeah. I could see a six gallon tank working as an absolute minimum. Also, this calculation ignores how often you feed the tank, so you'd need to check your nitrates until you get it figured out anyway.

 

[Phenguin_m_lee]

thats great, now i know i have more than enough....but is there ever such a thing as too much water?

 

[Phenguin_m_lee]

thats great, now i know i have more than enough....but is there ever such a thing as too much water?

i mean it might sound stupid, but.....i just want to know

 

[wwhite]

if i have a 8'' jack dempsey and a 14'' eel in a 39 gallon, is it overstocked?

 

[shrimplette]

I wasjust talking with my husband about that. I just doesnt make sense if you think it through. everything grows according to its genetics, not the size of the enclosure. Otherwise there would be some pretty strange sized creatures in the world