A Cory Tank Size Question

Mazeus
  • #1
Hello all,

I've been reading The 101 Best Freshwater Nano Species by Mark Denaro and Rachel O'Leary. In the book cory habrosus and pgymy cories are identified as fine for a 10g. I've also heard Rachel O'Leary make this claim on her channel. However, on this forum the consensus seems to be no corries in anything less than a 20g. How have people reached this conclusion?

I don't plan on getting cories any time soon, but I am curious.
 
leftswerve
  • #2
1. People repeat what they have heard or read.
2. People interchange any size cory (you are referencing pygmy)
3. 10 gallon is just not a good tank for any fish that needs to get around.
there's my two pennies (or whatever you guys call em).
 
Mazeus
  • Thread Starter
  • #3
1. People repeat what they have heard or read.
2. People interchange any size cory (you are referencing pygmy)
3. 10 gallon is just not a good tank for any fish that needs to get around.
there's my two pennies (or whatever you guys call em).

Your two pence worth
 
aussieJJDude
  • #4
4. Different strokes for different folks. I totally believe a 10 gallon can be set up as a community for nano fish, and that the smaller cories (ones you mentioned) work fine in a 10g.
 
shutterbug13
  • #5
Someone on here, I believe it was Anders247, kept a species of pygmy cory (I don't remember which) in a ten gallon and when he moved them to much larger tank their behavior was very different.
 
Fanatic
  • #6
1. People repeat what they have heard or read.
2. People interchange any size cory (you are referencing pygmy)
3. 10 gallon is just not a good tank for any fish that needs to get around.
there's my two pennies (or whatever you guys call em).

"There's my two cents."
That's the phrase
 
Mazeus
  • Thread Starter
  • #7
Someone on here, I believe it was Anders247, kept a species of pygmy cory (I don't remember which) in a ten gallon and when he moved them to much larger tank their behavior was very different.
Hmm, it would be interesting to hear about anders experience. I wasn't planning on getting cories (and I don't even have a 10g) but I do like to read about the hobby, and this bit of information seemed quite different to what is regularly repeated on the forum.
 
DoubleDutch
  • #8
My two pence :

Only fish from nano-rivers fit in nano-tanks.
I seriously don't get why size of fish give them the name nano-fish.

Besides of that a nanotank is something completely different than a small tank.
A real nanotank is a expert-copy of a natural biotop, a small tank is a small tank and there's nothing nano to it.

In common waterparameters are by far more stabil in bigger tanks than in smaller ones. I think that is what it is about !

The bigger the tank, the bigger the shoal the more comfy they are (waterquality, social, etc etc....).
 
Anders247
  • #9
Yeah, I had pygmy cories in a 10g, and they were active at first, but got more and more sedentary as time went on. Once the surviving ones were moved, they were more active in the 20g.
 
aussieJJDude
  • #10
DoubleDutch: the size of the fish is the reason why they called nano! Due to being smaller than the average fish, they are 'nano' or dwarfed.

And the size of the fish IMO does relate to size of the tank. A smaller fish can live in a smaller tank a lot comfortably than a larger tank... will it prefer a larger tank, yep... but will it be fine in a smaller tank, also yes.

Since nano fish are a lot smaller than other fish, they have a smaller bioload and therefore you can stock 'more' and make a larger school than larger fish. Water quality in nano tanks just matter as much as larger tanks.


The term nano is from the Saltwater hobbyists, which we borrowed and never really bothered to look up the definition! Cause otherwise we would be calling a lot of the nano tanks out there as Pico Freshwater tanks - general consensus is under 5 -10 g; while nano is under 20g.
 
DoubleDutch
  • #11
DoubleDutch: the size of the fish is the reason why they called nano! Due to being smaller than the average fish, they are 'nano' or dwarfed.

And the size of the fish IMO does relate to size of the tank. A smaller fish can live in a smaller tank a lot comfortably than a larger tank... will it prefer a larger tank, yep... but will it be fine in a smaller tank, also yes.

Since nano fish are a lot smaller than other fish, they have a smaller bioload and therefore you can stock 'more' and make a larger school than larger fish. Water quality in nano tanks just matter as much as larger tanks.


The term nano is from the Saltwater hobbyists, which we borrowed and never really bothered to look up the definition! Cause otherwise we would be calling a lot of the nano tanks out there as Pico Freshwater tanks - general consensus is under 5 -10 g; while nano is under 20g.
aussieJJDude

Of course I know why that name is used for smaller fish, but I disagree that all smaller fish can be kept in smaller tanks only for "space"reasons. There are bigger fish that can be kept smaller and the other way around. My CPD are almost as big as my cardinals btw. Behavewise I think CPD do better in a community for instance (experiences)

And as said "nano-tank" is often (mis)used as a synonym for small tank, which is something completely different to me.
That exact is my main point.
A nanotank is a small tank, but a small tank isn't a nanotank !

I've several tanks and to be honest waterquality in my 55 litre tanks get worse (due to filtration a d a smaller body of water) than my 160 litre tanks. Same reason why I advise starters to start with a bigger tank instead of a smaller one.

Nothing wrong with a REAL nano-tank and fish kept by a nano-expert, but let us not confuse/mix those with a small tank started by a starter in the hobby. That's asking for disasters.

But as said : My opinion / two pence
 
Lunnietic
  • #12
Pygmies I personally wouldnt put in under a 15 gallon.

Usually when people are looking at cories, they are looking at one of the larger breeds. Brozen, Pepper, Albinos, etc. I often forget pygmies exist because in my area of the States they are very hard to find.
 
DoubleDutch
  • #13
Pygmies I personally wouldnt put in under a 15 gallon.

Usually when people are looking at cories, they are looking at one of the larger breeds. Brozen, Pepper, Albinos, etc. I often forget pygmies exist because in my area of the States they are very hard to find.
Funny thing is I am keeping (13) bronze in a 15G tank for years, pandas (13) recently (new ones) without any doubt but my experiences with pygmaeus and habrosus in these thanks were catastropic.
 
goldface
  • #14
We are in America, so everyone call it pennies, not pence .

Rachel O'leary knows her stuff. She is the Queen of Nano.
 
JB92668
  • #15
I would keep corries in a two foot tank a ten gal is two small in my opion
 
DoubleDutch
  • #16
We are in America, so everyone call it pennies, not pence .

Rachel O'leary knows her stuff. She is the Queen of Nano.
I am in Europe so use pence hahahaha.
Correct : Rachel I'leary is a (nano) specialist not a starter with a small tank.
Exact what I am trying to tell
 
goldface
  • #17
I am in Europe so use pence hahahaha.
Correct : Rachel I'leary is a (nano) specialist not a starter with a small tank.
Exact what I am trying to tell
If it ends in .com, you're in America. Lol. Kidding.

I wasn't arguing with you or anyone else. Just wanted to stay on topic .
 
Lunnietic
  • #18
Funny thing is I am keeping (13) bronze in a 15G tank for years, pandas (13) recently (new ones) without any doubt but my experiences with pygmaeus and habrosus in these thanks were catastropic.
I have a trio in a 20 gallon high that are brozen. They are moving to a 20 long as soon as I get my hands on one. They are all 3.5 inches long. They look so smashed in there.

But I find people with experience can always bend and break the rules. I wouldnt recommend a beginner to do the things more experienced fishkeepers can.
 
JB92668
  • #19
the bigger the tank the better
 
Mazeus
  • Thread Starter
  • #20
the bigger the tank the better
Yes, of course that's pretty much always the case.

I suppose I was asking the question to try and guage how opinions (and in turn advice) is formed on the forum. For me, I would always seek to find authoritative sources (books, journal articles) to inform my opinions. Having been a member of several forums over the year (not just fish related) I know that at times advice is given by one, often senior member, and then repeated as gospel by other members. This advice becomes the accepted truth without critical evidence based analysis of this advice. That said, with fish keeping I suspect it is art as much as science, and therefore the experience of members shouldn't be discounted just because they are not world renouned experts. However, I do think there is merit in examining the advice given to determine how we arrived at a "truth" or "fact".
 
Miaw
  • #21
are your best bet for small cory btw.

I don't think (pygmy corys) are true corys. No offense to anyone who does They act more like tetras and things for me.

I'd keep both in a 10g, I wouldn't buy pygmy if I wanted something that stuck to the bottom though.

But when you see corys in a 10 gallon and corys in a 50 gallon it's amazing to see them swim back and forth in the tank in a school. I guess it's maybe a bit selfish keeping them in a 10 gallon but who knows, you could be saving them from the next person who comes along and puts them in a 5 gallon
 
goldface
  • #22
who knows, you could be saving them from the next person who comes along and puts them in a 5 gallon
Or save them from slow starvation as an “algae eater”. Lol.
 
leftswerve
  • #23
4. along with what Lunnietic wrote, on these forums experience plays a major role in how responses are given.

Quite often the person posting is bending or lying about their abilities or situation, much less you can't call them out about it or they'll cry.
 
JB92668
  • #24
well said mazeus
 
Piaelliott
  • #25
I have 10 habrosus in a 20 gal long (30 inches).
I think the issue with the small cories is that they do better in larger groups and are more sensitve to water issues.
IMO, they are not extremely active only when looking for food but considering that they prefer a larger group and the fact that I don't like to see all my fish at once when I look into my tank, I wouldn't put them in a 10 gal.
 
Anders247
  • #26
are your best bet for small cory btw.

I don't think (pygmy corys) are true corys. No offense to anyone who does They act more like tetras and things for me.

I'd keep both in a 10g, I wouldn't buy pygmy if I wanted something that stuck to the bottom though.

But when you see corys in a 10 gallon and corys in a 50 gallon it's amazing to see them swim back and forth in the tank in a school. I guess it's maybe a bit selfish keeping them in a 10 gallon but who knows, you could be saving them from the next person who comes along and puts them in a 5 gallon
Depends how you define true..... I don't think Corydoras are in the genus because of their behavior similarity. It's the body shape and superficial similarities that make it. They're a cory, just with different habits than most.
 
Miaw
  • #27
I find pygmy cories to be less stout in body shape.

But I meant not true as in.. not truly in the spirit of corydoras
 

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