Stocking after fishless cycling

[Essjay]

In the Fishless Cyling method here http://www.fishforums.net/threads/cycling-your-new-fresh-water-tank-read-this-first.421488/ it says

"A major benefit of this fishless cycling method is that you can now fully stock your tank in one go. This means an average stocking level for your tank size. It certainly does not mean you can stock heavily or over stock"

This is because the tank will have grown more than enough bacteria to cope with the ammonia made by a tankful of fish during cycling.


However, it has been stated by several members recently that even after fishless cycling the tank should be stocked slowly, a few fish at a time. This is to allow the bacteria to multiply to cope with each batch of fish.
I do realise that there are more than two species of micro-organisms that need to grow, but the terms beneficial bacteria or just bacteria are often given as the reason for taking it slowly without explaining if this means filter bacteria or all micro-organisms.





This contradictory information will cause confusion for new fishkeepers.

Is it possible for someone to give an indication of which of these two stocking methods is correct - fully stock at one go or a few at a time?

 

[eaglesaquarium]

Well, the answer isn't a simple one. And there is some carryover of the 'old way' of cycling and the 'new way'. Doing a fishless cycle, then slowly stocking is a bit of a midway point.


On one hand... there's really no downside to stocking slowly, other than the fact that you would have overdosed ammonia for the amount of bioload you are giving the tank to start. Specifically using the 3 ppm recommended in that article will cover your full bioload for a tank. So, stocking slowing means that you could get away with a much lower ammonia level to start the cycle - 1ppm would make more sense and the entire process would take less time. BUT... the time to 'full stocking' would be greatly extended.


On the other hand... there is some downside in some cases to stocking fully immediately (but there are also some major, major benefits as well). If you are stocking a sensitive species, a species that greatly depends on the microfauna and microalgae of the tank, then stocking those species too soon can take some time. You'd want to wait until the tank is more mature and merely being 'cycled' wouldn't account for that.
But, stocking species like African cichlids or any semi-aggressive type community fish in stages would be a problem. These fish should always be added together, so that territories are not preset before other fish are added. Adding them all at once allows gives each fish an equal opportunity to claim their own territory as well.




So, in short, there's no real issue with the discrepant advice. Adding all at once serves a clear purpose and allows fish keepers to have what they ultimately want faster - a full tank of fish. BUT, the slower method also works fine and in some cases is ideal for the more sensitive species or for the species most dependent on a mature set-up.

 

[SFFishSticks]

I think the article is correct so long as you can quarantine fish from different tanks separately or deal with the consequences of quarantining together or using the main tank as quarantine. You must also keep adding ammonia daily and doing water changes for nitrates until the fish go in the main tank.


If you cycle at 3-4ppm ammonia, then only put 10% bio load in, most of the beneficial bacteria will die off and you're back to cycling by adding a few fish at a time and waiting for the cycle to adjust.


In a recent post I saw, the tank parameters were good, but needed a water change for nitrates, but not critical to the point of killing all the fish. Seemed more likely that one of the fish brought a disease that others were more susceptible to, an accidental cycle was started by changing all filter media, any number of reasons that were not "too many fish".

 

[eaglesaquarium]

You must also keep adding ammonia daily and doing water changes for nitrates until the fish go in the main tank.

If you cycle at 3-4ppm ammonia, then only put 10% bio load in, most of the beneficial bacteria will die off and you're back to cycling by adding a few fish at a time and waiting for the cycle to adjust.

These statements are inaccurate. First, the bacteria do not require daily additions of ammonia to survive... and they can easily go without bacteria for a few days easily up to a week without any addition of ammonia and not have a problem. In fact, even if it goes longer the bacteria do not immediately 'die' but instead 'go dormant' until more favorable conditions are available. The longer they are dormant they longer they stay dormant, but they can bounce back very quickly.

For example, if I am getting a new batch of fish coming to my tank after a cycle. I can dose ammonia on Tuesday to feed the bacteria. Water change on Thursday to remove the nitrates and add the fish on Friday or Saturday without any concerns about the bacteria.


Along the same lines... underfeeding the bacteria will cause the colony to shrink... but after the biofilm has been created for these bacteria, they will re-multiply to deal with a surge in ammonia quickly. An established colony can double in size in 12-24 hours easily. So, any ammonia or nitrite spike that may occur due to adding a larger group of fish later would be very short lived... and just a quick water change the day after, maybe two days... and the full cycle will be quickly reestablished again.

 

[SFFishSticks]

These statements are inaccurate. First, the bacteria do not require daily additions of ammonia to survive... and they can easily go without bacteria for a few days easily up to a week without any addition of ammonia and not have a problem. In fact, even if it goes longer the bacteria do not immediately 'die' but instead 'go dormant' until more favorable conditions are available. The longer they are dormant they longer they stay dormant, but they can bounce back very quickly.

For example, if I am getting a new batch of fish coming to my tank after a cycle. I can dose ammonia on Tuesday to feed the bacteria. Water change on Thursday to remove the nitrates and add the fish on Friday or Saturday without any concerns about the bacteria.
...

Yes, daily was an overstatement. I was thinking of the other thread where posters were talking about weeks of quarantine. I really just meant you need to keep the colony active and not forget about it once initially cycled.

I would, however, err on the side of continuing to add ammonia every few days to ensure the initial cycle is well established vs trusting it will immediately bounce back. It just costs a few extra water tests, which is well worth it IMO when getting a tank running.

 

[Byron]

I agree with eaglesaquarium, both posts. Re the Nitrosomonas sp. and Nitrospira sp. bacteria, they can survive weeks, sometimes months, in the suspended or "hibernation" type state, depending upon some other factors like water parameters and such. They can even live months in bottled bacteria supplements like Dr. Tim's One and Only and Tetra's SafeStart. The point is that the scientific data now shows they are not the weak fragile little creatures we used to believe.

On the initial question of adding fish to a "cycled" tank...another factor is the tank volume. Someone adding too many fish to a small tank will have a far greater risk of trouble than someone adding fish to a large tank where the water volume dissipates the ammonia more than it can in smaller tanks, given the same number of fish of same sizes.

I always mention live plants, so will again. Having some fast-growing plants, and floating plants are ideal for this, almost guarantees no problems. Plants take up ammonia very rapidly, faster than bacteria in tests, and they can assimilate quite a lot. A valuable safeguard even in a cycled tank.

Byron.

 

[Essjay]

I have to confess that I've only ever done two fishless cycles. When I first had fish 20 years ago we did not have access to the internet, and as I had fish before I had a tank (my sons won four goldfish at the fair) I had no option but a fish-in cycle. Since then I've used mature media when setting up a new tank or upgrading a tank.

The two fishless cycles were to see how they went, the first using the old add ammonia whenever it drops to zero method, the second using the method on here now. Because they were for a 26 litre tank which would hold just one male betta, I cycled using just 1 ppm ammonia and obviously had to add the full stock in one go

But I have been surprised to see some recent posts saying that with all fishless cycles fish should be added only a few at a time, and some advocating to add fish very slowly with up to 3 weeks between additions; these posts did not mention quarantining fish as the reason for going slowly. I know that sensitive fish should not be added for several months, but again this has not been given as the reason for slow stocking.

This is why I was interested to hear other views.