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Corydoras aeneus (Bronze/Green/Albino)in 10 Gallon? Getting conflicting information.

11672 Views 11 Replies 7 Participants Last post by  Thoth
I've been reading about corys and have decided I want some for my 10 gallon tank, with the possibility of a betta tankmate. I've not decided yet, however, on the type of cory I want. I was looking at the dwarf, pygmy and Salt & Pepper corys, but stumbled upon a care sheet for the Bronze Cory. I really like its reputation for hardiness. I like that I can get 3 different colors that will school together, but I'm not sure that my tank is big enough. Some reading I've done puts the minimum size at keeping them at 15 gallons, others 10, one even said 8 gallons!

I'm also seeing conflicting information on their max size. The most common max size I'm seeing is 2 inches, which would make me think that I could do four (minimum recommended number?) in my tank and still have the ability to do a betta. (Using the 1 inch/gallon rule). But I'm seeing some sources give a max size of over 3 inches, which would mean I can't even do more than three of them alone in the tank.

What's the real story on these corys? Anyone wanting to add other information for a newbie cory keeper, feel free to chime in even if slightly off topic.
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Hi there! :D
The bronze cories you can expect to hit 2-3". The females will grow larger and fatter than the males. The 1 inch per gallon rule is kind of poo (excuse me ;-)).
Has your 10 gallon been set up for a while? Has it been planted with live plants?
Corydoras like a sandy bottom, or at least smooth gravel. This is much more important for smaller species of cory.
The bronze cory is indeed a bit more hardy than other species, so even though it is larger, if you are still new you may decide you want them. :)

Tank size is one of the most commonly debated things in fish keeping. There isn't really anyway to say "a fish needs to be in this much water or it won't do well."

So yes, you can maintain a group of bronze cories long term in a 15, 10, 8, even 5 gallon.
However you need to consider that cories enjoy zooming around the tank together quite a bit.. There is a big difference in how much zoom room (haha) a 3" cory has vs a 1.5" cory, which is why many (most) people will tell you a 10 gallon is too small for bronze cories.

You are right however that the dwarf cories are much more delicate... you may not feel comfortable buying them as your first cories for this reason.

My suggestion is to look for some middle ground. I would recommend either Corydoras trilineatus or Corydoras paleatus.
You will notice that both of our profiles say the 10 gallon is too small... But both of these fish are hardy beginner cories and readily available in shops.
The three lined cory is often sold as julii cory, while the pepper cory is often sold as salt and pepper cory. (Because stores just like to make everything confusing..)
I own both species. I've found they are less active than my bronze cories... The three lined cories were my first non-betta fish, and if they survived me for so long then that should speak for hardiness. :lol: I started them in 10 gallons as well (a 15 gallon tank with a 10 and 5 section). After a year I got a 20 gallon long tank and moved them in. :) So you may eventually decide to get a bigger tank (because yay more cories!). I would get 5 to start with.
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Information overload!

Firstly, welcome to TFK! :wave:

I know if can be an information overload when first researching a species of fish for our aquariums! Cories are a popular choice for a ten gallon but that doesn't mean they are a good choice. Generally, we like to recommend corydoras hasborus for ten gallon tanks as most other species simply get too large or too active for this sized tank. The bronze cory does reach an excess of 3" and is recommended only for larger sized tanks (55+) while the albino and green varieties as well as all others need at least 20 gallons. The one inch per gallon rule has been proven incorrect because using that method, you could house a 10" oscar in a 20 gallon tank when an aquarium of at least 75 gallons is needed for a lone oscar. I also want to make note that you cannot mix cories to form a school. If you want albino cories, you have to have at least 6 albino cories, if you want panda cories, you have to have at least 6 panda cories, and so on. Is you tank cycled?

I recommend the following stocking -

1 Betta
6 Ember Tetras
6 Corydoras Hasborus
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Firstly, welcome to TFK! :wave:

I also want to make note that you cannot mix cories to form a school. If you want albino cories, you have to have at least 6 albino cories, if you want panda cories, you have to have at least 6 panda cories, and so on. Is you tank cycled?
Thanks for the welcome!

I was under the strong impression that if they were the same species, Corydoras aeneus in this case, you could have the different morphologies and they would school. This was one of the main things I liked about aeneus, three morphologies in one species. Has anyone here have first hand account of this working, or failing to?

The tank is in the process of a fishless cycle using Ace Hardware pure Ammonia (after a truly obnoxious debacle of using unpure ammonia and having to clean everything). I would not be getting fish until it is fully cycled. If I were to go with dwarf cory species of any type, I would have a betta alone in the tank for 3-6 months first to make sure the tank is fully mature. I will be planting with low-light friendly plants, but will not be upgrading my hood or doing CO2 injection for a true "planted tank" setup, at least at first. I might do periodic yeast-fueled CO2 injection after adding a new plant.
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The "Green" cory is a likely brochis species which gets longer than the bronze.
The albino cories are almost surely the same species as the bronze so they should stay together.
They will school out of necessity, not because they want to.

I'm glad you cycled, does your tank have flourescent bulbs or yellow, incandescent bulbs? Also, I would add other fish AND THEN your betta. He could be a bit mean after having such a large tank to himself and then being forced to share.
They will school out of necessity, not because they want to.

I'm glad you cycled, does your tank have flourescent bulbs or yellow, incandescent bulbs? Also, I would add other fish AND THEN your betta. He could be a bit mean after having such a large tank to himself and then being forced to share.
Just running incandescent, which is why I'm going for low-light plants.

I would be doing a tank re-arrange when adding new fish, so it wouldn't be as big of a deal, but yes, I would prefer to have the tankmates first for most potential tankmates. The exception being is that any fish that are less hardy, I like putting into a more established tank, with less risk of mini-cycles or other problems that can happen with tanks that have just cycled. I could get a third hardy tankmate species I suppose, add it to the tank first, then the dwarf corys, then the betta, but I'm really not sure what fish that first fish would be. I'd want something with an ultra-low bioload that will be potentially compatible with a betta and corys, and would add a characteristic to the finished tank it doesn't already have. (A new color, a different behavior pattern etc.)
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Incandescent lights won't grow even low light plants, unfortunately. Walmart sells 13w 6500k flourescent bulbs for $5 a piece in the fish section, however. :thumbsup:

Ember tetras aren't too sensitive, so you could start out with those, then the cories, then the betta if you wanted.
How to do everything wrong and still have happy Corys

I started out with Mollies and 4 Bronze Corys in a 20 G tank. It was important to have enough Corys to make a collection of them, although not really enough for a school. I thought I had 2 males and 2 females, although I can't figure out which gender one is because it is slender and is a challenge to get right. But one female laid eggs pretty soon after I got them, which another one ate right off the bat; so I watched them carefully and the next time she spawned, I was able to scoop the eggs up and move them to another tank. There are a lot of tips to hatching and growing Corys, but now I have 20 babies and 4 adults. I have them in a 10 G tank by themselves over the last week, and the adults really haven't gotten to 3", more like 2" for the 2 females. The babies are still pretty small, so the whole process of figuring how many can fit in a tank is a bit of a question.

Because I was new to this, I chose the Bronze Cory because it is sturdy, peaceful with Mollies, and easy to raise, if you want babies. It doesn't have the designer look of the Salt & Pepper, but it has a green sheen to its body that is pretty, even though plainer. It is amusing that in the new tank, all the babies come out to eat when I put their sinking pellets in, but if I just walk by, they all disappear in a second. Underneath caves, behind foliage, under a rock, etc. all of them flutter away. I think they saw the parents do this, so they follow, even though they know I am safe, won't bother them, and feed them, too.

These Corys want to hide in the daytime, so keep them in a lower light environment for their pleasure. If you have a brightly lit tank, you won't see them much at all. They will come out if they must, but you have to provide them with places to shelter themselves, and to scoot when they want. But when so many are out and about, they are vastly entertaining with their swooping and swiping around, their feeding, and their falling over one another all the time.

When it is the first time you setup a tank, it seems to me better to try it with a good easy-to-handle species like the Bronze Cory, rather than lose some that are harder to do. I like success, don't start off with a possible hard to handle choice. JMHO and now I can watch mine and have fun with them.
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The site is an excellent online reference for info on a type of fish. This site will give you the habitat, max size as adult, minimum number to have for them to be happy, feel safe and thus be healthy, minimum tank size, food, and lots more. It is my 'go to' site any time I am considering another fish, or just curious about one.

My 50 gallon tank has 4 bronze and 6 gold aeneus. Of the 10, 9 are a good chunky 3 inches. One is slightly smaller.

I wouldn't think you can keep any aeneus in a 10 gallon. I suggest you read up on the smaller corys, pygmy, panda, etc. I just added some panda corys to my 37 gallon yesterday!
FWIW, my 3 Albino and 2 Green Corydoras never shoaled together (except around feeding time when they would peacefully share pellets). The Albinos (who were added first) are very fast and go all over the tank seemingly all the time. they are always aware of each other, but do not constantly stay in a tight group. The Greens (male, female) stayed very tightly together always and were quite slow and peaceful staying along the bottom. The difference in behavior may have led to their not shoaling all together. As I only have a 10 gallon and wanted a proper shoal, I have removed the 2 Greens and am looking to add Albinos.

Of note, my 8 Glowlight Tetras (from two separate purchases of 4) are always pretty tightly together in the left to center of the aquarium (in filter flow, but may be coincidence). The Albinos tend to go all around the tank perimeter essentially "surrounding" the Tetras.

I note I have very soft water (1-1.5 dKH) which my research has shown is good for all species I mentioned above.
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Necroing an old thread but anyway....

The internet is full of conflicting information; Hearsay, opinion and the short version are the norm. I think many responses fall into the short version as posters typically don't want to read or write of novel.

C. aeneus will reach 3" TL; I have a group of 3+ year old fish in one of my tanks. Personally, I believe in keeping cory in a group of no less than 5 so that more normal behavior can be seen. Tank size can play into normal behavior and I recommend 20 gallon long for all beginners. Cory can be kept in a 10 gallon and I know of a breeder that keeps most of his Cory in 10 gallon tanks with great success. So to answer your question, a shoal of Cory and a Betta will not overstock a 10 gallon tank unless you neglect your cleaning or overfeed.

In an aquarium, Cory are a shoaling fish; meaning that they will stay near other fish of the same genus/species to gain benefits of finding food, a mate or protection. Shoaling does not mean that they will swim in a tight group, moving as one. That is considered schooling which is seen in many commonly available tetras. These are two different terms that are incorrectly interchanged.

Variation in fish measurements can be from posters not referencing or being unaware of different fish measurement standards. I think most people are referencing TL while a smaller amount reference the SL but it can also vary based on topic. I think of SL length when stocking and TL for most everything else. These terms are useful in science articles and sport fishing.

SL, standard length, tip of the fish to the beginning of the caudal fin
TL, Total length, tip of the fish to the end of the caudal.
FL, Forked length, tip of the fish to the fork of the caudal fin.
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