How many fish can you add at once?

[Amortiogar]

My tank is 20gal tall and it's in its last stages of cycling. I had the water tested today at my lfs and they said the ammonia and nitrite/nitrate levels are lowering. I'm wondering how many fish I can add at one time, and what would happen to the levels if I add too many. Currently I'd like to add 4 cories and one indian pea puffer. Can I add them all at the same time?

 

[Mcgolg76]

Pea puffer could totally terrorize the Cory's

 

[Amortiogar]

Pea puffer could totally terrorize the Cory's

I've had them in my other tank for a week or so and they haven't been bothered by it.

 

[jwh0818]

If your doing a fish in cycle then maybe 2 to 3 but each time you need to expect to see a mini cycle because with a fish in cycle, your beneficial bacteria is only growing to sustain your current bio load. You should really get an API Master Test Kit to test your own water

 

[Terrance]

I've had them in my other tank for a week or so and they haven't been bothered by it.

It could take months or maybe 1-2 years before problems arise. Or it may never happen.

 

[BBradbury]

Hello Am...

If you're cycling a tank with fish, you don't add any until you have several daily tests with "0" ammonia and nitrite. Once your tank has no traces of these two toxins for several days, then you can add a few small fish. If you do add the fish, then you must resume testing daily for ammonia and nitrite and changing out a quarter of the tank water to get it back into the "safe zone" for the fish.

B

 

[Amortiogar]

Hello Am...

If you're cycling a tank with fish, you don't add any until you have several daily tests with "0" ammonia and nitrite. Once your tank has no traces of these two toxins for several days, then you can add a few small fish. If you do add the fish, then you must resume testing daily for ammonia and nitrite and changing out a quarter of the tank water to get it back into the "safe zone" for the fish.

B

Thank you, this was the type of answer I was looking for.