How Many Corydoras Trilineatus Can Live In A 20-gallon Long?

[bluedreams21]

Aqadvisor.com suggests 23 corydoras maximum assuming there are no other fish, but I feel like if I had 23 cories in a 20-gallon I'd have people from the forum throwing things at me.

 

[DarkOne]

Depending on your filter, 10-12 would be a good number.

 

[Sarah73]

5-10 would be better to start out with them add from there

 

[75g Discus Tank]

I'd start with 6.

Every week, slowly add 1-2 cories. Test rigorously. When you have over 40 nitrates before a weekly WC, you are a bit overstocked.

 

[Sarah73]

I don't mean put 5-10 all at once. Add three at a time maybe and don't wait until 40 nitrates to know if your over stocked. What kind of filter do you have?

 

[bluedreams21]

I've already had 7 corydoras in mine for months, I'm just wondering what I could reasonably consider increasing the number to over the next few years. Have an Aquaclear 50.

 

[DoubleDutch]

Just curious : Why would you add 1-2 corys at the time in a cycled tank (assuming it is cause I wouldn't add corys in an uncycled one). Everytime when you do this there is a risk of bringing in new diseases / contamination. I would always try to introduce a complete group. It also prevents the first ones to stess out (again a possible cause for diseases). Also when healthproblems you can treat all at once.

I'd start with 6.

Every week, slowly add 1-2 cories. Test rigorously. When you have over 40 nitrates before a weekly WC, you are a bit overstocked.

 

[75g Discus Tank]

Just curious : Why would you add 1-2 corys at the time in a cycled tank (assuming it is cause I wouldn't add corys in an uncycled one). Everytime when you do this there is a risk of bringing in new diseases / contamination. I would always try to introduce a complete group. It also prevents the first ones to stess out (again a possible cause for diseases). Also when healthproblems you can treat all at once.

If you’re unsure of how many cories you want to add, I would do it this way to make sure the spike in ammonia, nitrites, or nitrates won’t affect the fish too badly and you can see where the “perfect” stocking level is.

To amend this idea, how about keeping the group on a QT tank and slowly add them into the 20 long? Like start with 6 healthy cories and slowly add QT cories(if their healthy) over the weeks so the fish will be healthy and you can make sure that the parameters won’t spike too much.

 

[Kysarkel000]

Id say 12 is a good number. One large school, or two smaller schools would look nice. I feel like 23 of them would be okay temporarily if you were breeding or something lol.

What else is going into this tank?

 

[Sarah73]

Aquaadvisor isn't a good resource to help know if your over stocking, under stocking, or perfect.