After The Cycle Is Done...

[Glod]

Hi,

I recently started the community tank in my sig, it's been running for nearly 2 months now and the cycle seemed to finish after about 4 weeks or so. The cycling was done with some platys rather than fishless as I hadn't read the fishless cycling stuff at the time.

Last week I added the tetras and the plecs and have been monitoring the ammonia/nitrite/nitrate but didn't really see any more than a tiny rise in ammonia or nitrite in the last week. (Nitrate is still about 8ppm and not rising very quickly.)

I do regular water changes, about 20-25% a week with a gravel vac at the same time, perhaps slightly more frequently during the ammonia and nitrite spikes to keep my fish healthy. They all seem content, the platy are spawning in their traditional fashion... I gave up counting the fry now, every time I look there seems to be a few more

Anyway my question is, when adding more fish to the tank, obviously I only want to add a few inches at a time so I don't overload the bacteria in the filter and cause the tank to start cycling again. I believe the bacteria in question can double in number in about 24 hours does this mean that *if* I add a few fish and after a couple of days the ammonia/nitrite remain at 0 I can think about adding a few more ?

It's a big tank (to me anyway.. and pretty sparsely populated I think so I'd like to start getting some more fish in there. The plan is to keep them all as smallish fish 2 inches is the general guideline size, tho in the future I would like to add a few slightly larger ones, maybe a Dwarf Gourami or a pair of Rams or Kribensis and a few Rainbowfish...

Anyway, how long would you reccomend between batches ? (Assuming no other factors such as disease play a part.)

 

[Fwapp]

When initially stocking mine, I waited a week between adding 4-6" worth of fish/week, which gave no problems. It also helped that that was the day (Sunday) when the wife was at work and did'nt know I was buying fish!

 

[Tsi_User]

We added about 6 inches a week to our 30 gallon community also. Even 24 hours after adding them there weren't any spikes

 

[Glod]

Thanks guys, I've been testing daily and haven't seen any kind of spike so your answers confirm my thoughts

I think I will leave it a week between batches which will also give me time to make sure any new additions are healthy. Just in case.

Now I need to go find out what my dad is after next week

 

[smmetz]

Also, remember that when adding fish, the number of inches you add is not as important to consider as the % increase. For example, if you only cycled with 5" of fish, adding 5 more inches will tank longer to balance out again than if you already have 20" of fish in there. So, the more fish you have in the tank, the more you can add at one time. (assuming you have room in the tank, I am not advocating overstocking your tanks, obviously)

 

[Glod]

Good point smmetz.

The last couple of batches have been small fish like the Cardinal Teras and Harlequin Rasorbas (and of course the tiny plecs.) Generally less than half what was in there to cycle with (10 platies).

Everything seems to be stable, not even seen a blip in the ammonia / nitrite which is good.