# How many corys can I add to my new tank at once?



## Leeatl (Aug 8, 2015)

You can use an ammonia calculator like this....https://www.fishforums.net/aquarium-calculator.htm ...and get the tank up to processing 3-4ppm of ammonia in 24 hrs and I think you would be ok to add the Corys . Even then I would check ammonia/nitrite daily after you add fish and keep some Prime on hand just in case .


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## KaylSoftpaws (Aug 23, 2019)

What she said. And 10-12 is a good number. You could safely do 20, honestly--I have 13 c. habrosus and 8 c. pygmeus in a 29 gallon and they're not cramped at all.


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## ElleDee (May 16, 2020)

Leeatl said:


> You can use an ammonia calculator like this....https://www.fishforums.net/aquarium-calculator.htm ...and get the tank up to processing 3-4ppm of ammonia in 24 hrs and I think you would be ok to add the Corys . Even then I would check ammonia/nitrite daily after you add fish and keep some Prime on hand just in case .


I can work towards 3-4 ppm of ammonia a day. I was doing 1 ppm a day until a few days ago anticipating this issue but had stopped because I was worried about algae. I can spread out the drops throughout the day so there's no sudden spike. That's probably more realistic anyway. I've got plenty of Prime on hand if I need to tie up some nitrogen.




KaylSoftpaws said:


> What she said. And 10-12 is a good number. You could safely do 20, honestly--I have 13 c. habrosus and 8 c. pygmeus in a 29 gallon and they're not cramped at all.


I may add more in the long run, but I am leaving it understocked until I have a plan for what is going in the fully stocked tank. The corys were the only thing I am set on having, so they get to rule the roost while I think it over.

Thanks for the input! I'll let y'all know how it goes.


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## ElleDee (May 16, 2020)

So, I have been adding ammonia, but the corys weren't available with no availability in sight, so I ended up picking up 8 white clouds. They were on my consideration list anyway and just looked so lively in the store. Now at home they are swimming all over the place and the males are sparring, very fun. There has been no ammonia spike yet; I'll keep watching it. I feel like it's going to be fine though! The white clouds are so tiny and my plants have put on a lot of growth this week. I expect things to get a little out of whack, but it'll be manageable.


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## Discusluv (Dec 24, 2017)

As a rule, when I add new fish I change 25%-50% ( depending on bio-load) of water for the next 3 days to ensure there is no spike of ammonia and or nitrites. 
Within 72 hours the biofilter should catch up with the current bioload. 
Why guess it will be fine when you can ensure it will be fine.


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## butchblack (Oct 25, 2019)

I have 12 hastatus corys and a betta in my 10g, and it's fine. Are you setting up a nano fish tank as the habrosus only gets to be about 3/4" long? I found this site helpful for determining stocking levels.

AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor 

The one bit of advice I would offer is to make a plan of what fish you want to keep in it. That way, both stocking levels, and compatibility can be addressed before you buy your fish.


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## ElleDee (May 16, 2020)

Discusluv said:


> As a rule, when I add new fish I change 25%-50% ( depending on bio-load) of water for the next 3 days to ensure there is no spike of ammonia and or nitrites.
> Within 72 hours the biofilter should catch up with the current bioload.
> Why guess it will be fine when you can ensure it will be fine.


I can do that. 



butchblack said:


> I have 12 hastatus corys and a betta in my 10g, and it's fine. Are you setting up a nano fish tank as the habrosus only gets to be about 3/4" long?


Yup, just nano fish, I think! Probably just the white clouds and something else. I'd like the corys, but I'd have to find some available to me. (Though also don't love that they are mostly wild caught - I'd much prefer tank raised fish across the board.) I might end up going in a different direction when it comes down to it, but compatibility with the existing tank is paramount.


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## TommyLee (May 30, 2020)

I have 10 gallon tank and 8 Neon tetras, 3 pygmy Corys and some red cherry shrimps. With regular water change and vacumm cleaning, I have no issues in tank apart from regular cleanning.


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