29 Gallon Stocking Advice

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jj22

Aquarium Advice Newbie
Joined
Nov 13, 2024
Messages
2
Location
Canada
Hi,
I have a some questions about stocking my 29 gallon tank (30x12x18). I’ve asked on another forum but the more opinions the better.

Detailed Info:
Using a Fluval 307 filter and I do weekly water changes of up to 30% or so - sometimes up to 40% or so.
Have a couple very small anubias nana plants attached to driftwood (x2), bunch of artificial plants, another cave-like decoration, circulation pump and the substrate is gravel.

I currently have 9 Diamond Tetras (6m, 3f) and 1 Bristlenose Pleco (m).
I’m thinking of adding 5 Corydoras for the bottom (most likely Sterbai - I’ve read they’re hardy and better for the warmer water needs of the other fish but I’m still researching). I would like 6 or even more but am concerned about overstocking.

(Also been debating adding more female Tetras, read it may be better to have a higher f-to-m ratio but also heard it doesn’t matter. And I think I’d prefer keeping the 9 l have and adding more Corys instead).


Questions:
  1. What’s the ideal number of Corys to add? I’d like 6 but is 5 the most I should go? (Can I get more if they are mostly male?)
  2. How many female and male Corys would be ideal? Do ratios matter if I’m not planning to breed them? I want mostly males, I know females get bigger but I’d like to have at least 1.
  3. Is it necessary to get more Tetra females for their happiness? If so, I know it would obviously affect how many Corys I can add.
*note: I’ve been thinking a larger male to female ratio is best as I’m not wanting a lot of breeding to go on, but am ok if it happens.

Those are all the questions I can think of for now, any help is much appreciated and other stocking ideas are welcome too.

Thanks!
 
Last edited:
Hi,
I have a some questions about stocking my 29 gallon tank (30x12x18). I’ve asked on another forum but the more opinions the better.

Detailed Info:
Using a Fluval 307 filter and I do weekly water changes of up to 30% or so - sometimes up to 40% or so.
Have a couple very small anubias nana plants attached to driftwood (x2), bunch of artificial plants, another cave-like decoration, circulation pump and the substrate is gravel.

I currently have 9 Diamond Tetras (6m, 3f) and 1 Bristlenose Pleco (m).
I’m thinking of adding 5 Corydoras for the bottom (most likely Sterbai - I’ve read they’re hardy and better for the warmer water needs of the other fish but I’m still researching). I would like 6 or even more but am concerned about overstocking.

(Also been debating adding more female Tetras, read it may be better to have a higher f-to-m ratio but also heard it doesn’t matter. And I think I’d prefer keeping the 9 l have and adding more Corys instead).


Questions:
  1. What’s the ideal number of Corys to add? I’d like 6 but is 5 the most I should go? (Can I get more if they are mostly male?)
  2. How many female and male Corys would be ideal? Do ratios matter if I’m not planning to breed them? I want mostly males, I know females get bigger but I’d like to have at least 1.
  3. Is it necessary to get more Tetra females for their happiness? If so, I know it would obviously affect how many Corys I can add.
*note: I’ve been thinking a larger male to female ratio is best as I’m not wanting a lot of breeding to go on, but am ok if it happens.

Those are all the questions I can think of for now, any help is much appreciated and other stocking ideas are welcome too.

Thanks!
The good news is that because you are keeping fish that will inhabit different layers of the tank, overcrowding will not really be an issue stock wise but you will need to keep an eye on your nitrate level as there will be a lot of mouths you're feeding which will be creating more eventual nitrates. In Tetras, you want more females than males OR all males because when they come into breeding age and condition, the males will fight amongst themselves for breeding rights ( whether you want them to or not. ) if there are females present. I would consider rehoming 3 of your males and adding back 6 females or switch out all the females and replace them with males.
With the Cories, if you don't want them breeding, get all males. I had good success with the Sterbai in my hatchery which was air conditioned to 78-80F degrees by design. 6 is fine in a 29. If you were deliberately breeding them, 2-3 males per female would be the ratio. If you don't care if they breed, the ratio doesn't really matter with Cories as much. That said, you may have an issue if there is only 1 female and 5 males. They may pester her to death. I'd do 2 females and 4 males unless you go all males.

Just a side thought on overstocking. What most people do is get fish that inhabit the same level in an aquarium. When this happens, there is a lot of "rubbing elbows" and getting into each other's way which can cause fighting ( depending on the specie.) When you add fish that live in the different levels in the tank ( Top, Middle and Bottom) you can add more fish than the " recommended" stocking numbers. The key is that the more fish you have in a tank, the more nitrates will rise faster so that is one downside of overstocking. That is remedied by more frequent water changes, not necessarily larger volume water changes less frequently. Plan on weekly changes or twice weekly if your nitrates rise to over 20 ppm in that week. The lower they are, the better.
Hope this helps (y)
 
The good news is that because you are keeping fish that will inhabit different layers of the tank, overcrowding will not really be an issue stock wise but you will need to keep an eye on your nitrate level as there will be a lot of mouths you're feeding which will be creating more eventual nitrates. In Tetras, you want more females than males OR all males because when they come into breeding age and condition, the males will fight amongst themselves for breeding rights ( whether you want them to or not. ) if there are females present. I would consider rehoming 3 of your males and adding back 6 females or switch out all the females and replace them with males.
With the Cories, if you don't want them breeding, get all males. I had good success with the Sterbai in my hatchery which was air conditioned to 78-80F degrees by design. 6 is fine in a 29. If you were deliberately breeding them, 2-3 males per female would be the ratio. If you don't care if they breed, the ratio doesn't really matter with Cories as much. That said, you may have an issue if there is only 1 female and 5 males. They may pester her to death. I'd do 2 females and 4 males unless you go all males.

Just a side thought on overstocking. What most people do is get fish that inhabit the same level in an aquarium. When this happens, there is a lot of "rubbing elbows" and getting into each other's way which can cause fighting ( depending on the specie.) When you add fish that live in the different levels in the tank ( Top, Middle and Bottom) you can add more fish than the " recommended" stocking numbers. The key is that the more fish you have in a tank, the more nitrates will rise faster so that is one downside of overstocking. That is remedied by more frequent water changes, not necessarily larger volume water changes less frequently. Plan on weekly changes or twice weekly if your nitrates rise to over 20 ppm in that week. The lower they are, the better.
Hope this helps (y)
Thank you so much for your response, definitely helped a lot! I will try to switch out the Tetra females for males. Would it be really bad if I left them as is?

Great to hear about the Corys - just clarifying if 6 is the most I should go?
- If I went 2 females, is 4 males the most I should go?
- And if I went all males, would I be able to add one or two more since they’re smaller?

Thanks again and appreciate all the advice on overstocking!
 
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With the Tetras, leaving them as is is an option but you should expect there to be some squabbles in the future. What usually happens is that one or both of the fighters get torn up a bit. When there is enough room and hiding places for the loser to escape to, that's usually how it ends. If there isn't however, the winner could beat up the loser to death.

With the cories, it depends on which specie you go with ( smaller vs larger species) but in the case of Sterbai, 8 males would still fit. Mine liked to play in the current as well. (y)
 

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