TFA101

recently, I have learned thath this rule isn't as helpful as it could be.

one 6-inch oscar could easily out-pollute three 2-inch harlenquin fish. So, if this is the case, is it possible to add more than, for example, 20" of fish in a 20 gallon tank?

sirdarksol

Precisely. This is why it's the 1"/gallon guideline. It only functions in the cases of smaller fish, and certain fish produce more waste than their mass would suggest.

TFA101

so, following this guideline prevents you from overstocking when it comes to smaller fish like neons?

Lucy

That's exactly why I add ......depending on the fish when advising about the 1" rule.
Another example is you couldn't put a 10" fish in a 10g tank.

Chief_waterchanger

I never liked that guideline, but sadly it is something newcomers will atleast halfway listen to and until there is a better way to get people to listen to advice some use such loosely-based, rarely accurate type of thing.

seedy

Hi everyone
I agree with what has been said so far .
The 1" rule has many exceptions to it , but it does make people think about how to stock the tank they have .

04_si

im not a pro by any means, but i think 1" per gallon is good for a peaceful community tank

TFA101

would it still be accurate enough for my biggest fish, the angels and the "flyer"

Chief_waterchanger

It is not accurate for angelfish, no. Angelfish need atleast 29 gallons (more height than length, if available) to properly form their fins.

TFA101

this is 29 gallons per one angelfish?

sirdarksol

Not sure, but usually it's a base amount of space for a fish like an angel, and then a smaller addition for each additional.
For example, Goldfish need around 30g for the first, and an additional 10g for each following fish.

Lucy's right about the ten gallon tank. Other than really small fish (think neons), and fish that can get along on their own (think bettas), a ten gallon isn't really big enough for much of anything.
Some fish also need more swimming space. Mollies, for example, are pretty energetic and need to burn their energy. You can still get pretty close to the 1" per gallon with them, but you can't keep them in anything less than a 20g (and I'd go with a 29g tall, at least, as they like vertical swimming space).

TFA101

the 20 gallon was hypothetical. my new stock is going to be

3 angels (koi, black marble, silver striped)
10 Neon Tetras
1 Flying Fox
1 Ancistrus Catfish

I presume 50 gallons with this current stock is enough for the angels im planning to get? or shall I start looking for different tankmates?

miker

Angels with Neon Tetras?

Chief_waterchanger

I'm sorry, I should've been clearer. I should've said, "29g for angelfish is big enough for 2 full size adult angelfish and a few well-thought out tank-mates."

The 29g is mainly for plenty of room for fin growth. (If angelfish are kept in too short of an aquarium or heavily overstocked conditions they get bent fins.)

I have no experience with the flying foxes, so I'll leave that one for someone else, but I can comment on other choices.

3 angelfish and the ancistrus will definately enjoy a 50g+ tank. I would keep an eye on the tetras. The angelfish may not bother them, but then again they may devour them as though they were that day's meal. It is impossible to tell until you know the personality of the angelfish.