Time fram for the Bioload adjusting after adding new fish

[garth7]

Quick question.....

How long does it take for the bioload to adjust after adding fish to a tank.

I realize this will be different for different situations. This is mine:

I had the tanks cycled (ammonia at 0 and nitrites at 0). I added two dwarf gouramis and noticed no real spike in ammonia or nitrates. I am assuming my fishless cycle built up the bioload to handle these to fish in my 55 gal. I then a week later added 6 white clouds (less that .5 inches each) and two ottos about an inch each. I have been testing and testing and never noticed a spike in the ammonia or nitrites.

I would assume I would get a little spike. Am I wrong for assuming this? Would you think a week would be enought time if I wanted to add another fish?

Give me your thoughts and thanks in advance!
Doug

 

[JDogg]

i would think that if you are waiting a week between adding a few fish you should be fine and should have not noticed a spike in ammonia....

i did a fishless cycle on my 75 and them added the whole bioload of my 28 and never saw any ammonia...that was like 15 fish... :d

 

[garth7]

That sounds good. I just am trying to have very few fatalities.... and that includes my bank account... lol I would assume if I added a big load of fish I would see an increas in ammonia. But in second thought I guess that the ammonia would only spike if I exceeded my bio load....

 

[TomK2]

Most would add the fish in one to two week intervals. If you can, save the largest bioload increased for the last. That would mean large schools or large fish last. In practicallity, after the first few additions spaced a week apart, your bioload is going to be very capable. Those bacteria exist in large numbers, each one subsiting on trace ammonia and nitrite. When you increase the bioload later on, not only can the bacteria double every 7 to 14 hours (which is a significant response ability with an established biofilter but not when you are starting from scratch with very few bacteria), but they can increase the amount they metablolize while waiting to double.

Thus, I would expect that you would not see any ammonia or nitrite spikes with weekly modest additions of fish. Perhaps going from 1/4 bioload to 110% bioload in one week might get you in trouble, but not weekly modest additions.

 

[garth7]

Thanks for the advice! I think I am going to wait a bit and research my next purchase though.... (probably not but I am going to try)

 

[7Enigma]

The whole purpose of doing a fishless cycle is to be able to fully stock your tank at the end with no fear of a cycle. All of the numbers we keep throwing around are concentrations, so 1 fish in a 10gallon and 10 fish in a 100gallon are making essentially the same amount of waste for their container.

If you properly build a biological filter from fishless cycling that can tackle 1-2ppm per 12-24 hours you will NOT have a cycle in your tank unless you OVERSTOCK. Stocking fully for the size tank you have will go unnoticed. Things like feeding less or less frequently when you first add them in is a good thing since they will probably be stressed which increases their metabolism and the waste that is produced.

When you do a fishless cycle and then only add a portion of the bioload, some of your biological filter WILL DIE OFF. If you fully stock at once you don't really care since whatever dies off isn't really required at that time. As the fish get bigger the bacterial population will increase along with the fish since they will expand to their food source (ammonia and nitrIte). I personally feel the WORST thing you can do in a fishless cycle is to save the largest bioload addition at the END. Your bacterial population has DECREASED from where it started prior to adding fish, and now you are going to add in the largest increase in ammonia? It doesn't add up.

It's a sticky situation on this forum, however, because very few people ever make it to completion with a properly performed fishless cycle. Normally we get the, "I just had to get him, I know my tank's not ready yet, but I just couldn't resist" crowd. Because of this common occurrance most members (including myself some time) will NOT recommend a full stock at once, but instead to go slowly. This is done because not all of the measurements have been done accurately, or values reported truthfully.

When you increase the bioload later on, not only can the bacteria double every 7 to 14 hours (which is a significant response ability with an established biofilter but not when you are starting from scratch with very few bacteria), but they can increase the amount they metablolize while waiting to double.

Can you qualify this?

 

[TomK2]

Sure I can qualify it. I make some assumptions. If you assume that a complete metablolism of 1 ppm of ammonia per day is the same as the ammonia production of your full stock level, then going to full stock after complete fishless cycle eating 1ppm per day should work. I always strived to prevent ammonia and nitrite exposure to the fish, so I go conservatively. If my tank metabolises a certain amount, when I add fish I use a lesser estimated bioload to make sure things will work out. Which, of course, is just a guess based upon experience since there are no charts that state how much ammonia a given fish produces each day. I must also add that I find pleasure in going slower and adding stock over weeks.

The nitrosomas bacteria don't die off right away, but slow down activity and can even go dormant over a period of time before die off. Full Dormancy, however, is not a rapid response state for Nitrosomas. Thus, they have the ability to linger around in numbers waiting for the ammonia to return, and respond relatively quickly to it as long as they have not been completely cut off from ammonia for a prolonged time. The Nitrobacter are not obligate nitrite eaters, so their die off might also be slower than you think since they can subsist on nutrients other than nitrite.

But if you did have a biofilter that has significantly reduced in size, and lets say can only metabolize 0.25 ppm per day. It is 14 to 28 hours or less away from metabolizing 1 ppm per day with the published doubling times of Nitrosomas and Nitrobacter (7 and 14 hours). This is in stark contrast to a new tank, which has very, very little ammonia and nitrite metabolizing capacity. Even with the little buggers doubling right on time in a new tank, you can be weeks away from 1 ppm per day capacity.

I find no fault with dosing ammonia so that your tank can have a full bioload right away. Its just that I always enjoy building the community over several weeks (ie: lots of reasons to go to the LFS frequently!). Once over 50% stock, your biofilter can handle large increases in stock without a hiccup -those hungry biofilter bugs eat more and faster while they double their numbers in response to the stimulus of more food. Then when things stablilize, I beleive the biofilter colony consists of a larger number of bacteria getting just enough food each to live, rather than a smaller number doing all they can just to keep the levels down. Thus, the bacterial colony is always poised to take advantage of an increase in nutrients. In keeping with my philosphy of making sure I don't add fish too fast, the larger fish and larger schools are then added near the end of stocking when the biofilter is in its best position to respond to the extra nutrients.

 

[7Enigma]

Sure I can qualify it. I make some assumptions. If you assume that a complete metablolism of 1 ppm of ammonia per day is the same as the ammonia production of your full stock level, then going to full stock after complete fishless cycle eating 1ppm per day should work. I always strived to prevent ammonia and nitrite exposure to the fish, so I go conservatively. If my tank metabolises a certain amount, when I add fish I use a lesser estimated bioload to make sure things will work out. Which, of course, is just a guess based upon experience since there are no charts that state how much ammonia a given fish produces each day. I must also add that I find pleasure in going slower and adding stock over weeks.

The nitrosomas bacteria don't die off right away, but slow down activity and can even go dormant over a period of time before die off. Full Dormancy, however, is not a rapid response state for Nitrosomas. Thus, they have the ability to linger around in numbers waiting for the ammonia to return, and respond relatively quickly to it as long as they have not been completely cut off from ammonia for a prolonged time. The Nitrobacter are not obligate nitrite eaters, so their die off might also be slower than you think since they can subsist on nutrients other than nitrite.

But if you did have a biofilter that has significantly reduced in size, and lets say can only metabolize 0.25 ppm per day. It is 14 to 28 hours or less away from metabolizing 1 ppm per day with the published doubling times of Nitrosomas and Nitrobacter (7 and 14 hours). This is in stark contrast to a new tank, which has very, very little ammonia and nitrite metabolizing capacity. Even with the little buggers doubling right on time in a new tank, you can be weeks away from 1 ppm per day capacity.

I find no fault with dosing ammonia so that your tank can have a full bioload right away. Its just that I always enjoy building the community over several weeks (ie: lots of reasons to go to the LFS frequently!). Once over 50% stock, your biofilter can handle large increases in stock without a hiccup -those hungry biofilter bugs eat more and faster while they double their numbers in response to the stimulus of more food. Then when things stablilize, I beleive the biofilter colony consists of a larger number of bacteria getting just enough food each to live, rather than a smaller number doing all they can just to keep the levels down. Thus, the bacterial colony is always poised to take advantage of an increase in nutrients. In keeping with my philosphy of making sure I don't add fish too fast, the larger fish and larger schools are then added near the end of stocking when the biofilter is in its best position to respond to the extra nutrients.

IMO, the true goal of a fishless cycle is to produce an excess biofilter that can handle anything you throw at it. I personally shoot for the 2ppm in 12 hours on a new tank so I can be certain no matter what I do I'll never see even a hint of ammonia/nitrIte. You can most definately do less, and stay under acceptable levels (for me nothing but zero is acceptable), but I just don't want to chance my fish's health on not waiting an extra day or 2.

I said 1-2ppm in 12-24hours. I gave that range for a very specific reason. If you are stocking messy fish like goldfish or pleco's I would recommend being able to convert 2ppm in 12 hours. If you are putting in a bunch of juvenile tetras or other young fish you can probably get by on 1ppm every 24hours. It's not an exact science, but we have a pretty good idea of what fish naturally have a tendency to produce a lot/little waste. I also said properly stock, and that means not getting 10 goldfish for the 20 gallon tank because they are all small, that means stocking the same number of fish if you purchased all fry, or all adults. And again I would heavily lean towards the 2ppm in 12hours if all adults, and be more lax if younger.

The articles/papers I've read have shown that true dormancy among the nitrosomas bacteria require somewhere around 100ppm ammonia to become active again. I've also ready that they rapidly decrease in population when an adequate supply of ammonia is not present. I'll have to dig around and see where I read it, but it was quite shocking (something like within a few hours of limited ammonia/nitrIte numbers will reduce).

The doubling times you are quoting are optimal, that is they are laboratory tested to determine the maximum doubling rate. Our tanks cannot reach this point and because of that the normal doubling time falls between 15-20hours. I have an article in the articles section on speeding up the fishless cycle, but I can guarantee even if you use all those tricks your still not hitting the optimal doubling rate.

I have never read anything regarding eating more and faster when excess food is present. They are not magical, they have a set amount they can consume and as long as they are given enough they will continue to divide. Once they reach that point, there will be no appreciable net increase in population until there is a greater food source.

I still believe that adding in the largest school/bioload of fish after a successful fishless cycle is the best way to reduce the possibility of a spike later on down the road when you add more fish.

When I fishless cycled, I had a 14day cycle, I used a bunch of tricks to speed it up, and had some gravel from a friends established tank. I then added my tiger barbs first (largest group and largest bioload), followed by 3 other groups 24hours apart. I saw no cycle. At the time I was recommended to add slowly but after seeing zero detectable ammonia/nitrIte I continued to add in fish every day after work when I stopped by the LFS. I think this might be even better than adding all at once since I was able to monitor my levels before the next group was added, but not waiting long enough for the bacteria to begin to die off. At that time I was just going with what was recommended by the helpful folks on this site.

So I'll modify my statement and hopefully we can both agree :

Adding in your full complement of fish in groups spaced closely together (every 24-48 hours) where no detectable ammonia or nitrIte is present, is the best way to stock after a successful fishless cycle to prevent the possible mini-cycle if bacterial populations reduce from a lower bioload.

 

[TomK2]

7Enigma-

Different ways of acheiving the same goal. That is not exposing fish to ammonia and nitrite. Why, I even champion using fish to establish a bioload if you have the patience to stock very low and go very slow, a technique that is just as humane and effective as fishless. Of course, now that I have several established tanks, such things are no longer a problem. The miracle of seeding! But if adding larger increases in bioload at the end is not "the best" method, I can attest that it does indeed work and is not "the worst" method.

I also read that the optimal reactivation rate for dormant Nitrosomas was something like 200 ppm, optimal meaning the fastes reactivation rate. This stems from dormancy being an energy demand to get into that last ditch survival state, and the bacteria can not risk reactivation for a trivial or fleeting ammonia source. They will reactivate with a steady supply of much lower ammonia levels, albeit slower than maximum, and that is how we do fish and fishless cycles.

But the bacteria do live on "trace" amounts of ammonia. Obviously, less than the 0.25 ppm we can test for. While I have not explicitly researched nitrosomas or nitrobacter in the lab, living organisms are not typically on/off things, but have a range of metabolic activity, and thus a range of ammonia and nitrite metabloizing capacity. This is temperature, pH, and oxygen dependent at least, and I would think nutrient availability as well. Not expecting magic here, just to follow the ways other bacteria behave. Personal experience makes me think that ammonia availability in the inhabited tank is rather variable, depending on fish activity and feeding, decaying stuff and such. Unlike your big square test tube when doing a fishless cycle. Not seeing ammonia and nitrite pop up after fleeting changes in the inhabited tank makes me think the mature biofilter is capable of reacting to the varying loads we put on it, which is a darn good thing for us. Only explanation I have for this is that the bacteria can increase metabolism when the oportunity presents, since they certainly can't double fast enough to deal with transient changes. Hence the conclusion that the bacterial colony are many bacteria operating below maximum level rather than fewer bacteria operating at maximum. And even if they can only double once a day, that represents a significant response ability for a mature biofilter of many bacteria if a sustained change in ammonia load presents itself.

I am a wierdo, and actually enjoy reading about the nitrifying bacteria as much as the other inhabitants in my tank, as long as its not just a "journal of bugs" article published to keep the university types going -- it has to have some relevance to aquariums! Should you find your links and articles, perhaps we can swap some sources? I haven't searched any out in over a year myself.

 

[7Enigma]

7Enigma-

Different ways of acheiving the same goal. That is not exposing fish to ammonia and nitrite. Why, I even champion using fish to establish a bioload if you have the patience to stock very low and go very slow, a technique that is just as humane and effective as fishless. Of course, now that I have several established tanks, such things are no longer a problem. The miracle of seeding! But if adding larger increases in bioload at the end is not "the best" method, I can attest that it does indeed work and is not "the worst" method.

I also read that the optimal reactivation rate for dormant Nitrosomas was something like 200 ppm, optimal meaning the fastes reactivation rate. This stems from dormancy being an energy demand to get into that last ditch survival state, and the bacteria can not risk reactivation for a trivial or fleeting ammonia source. They will reactivate with a steady supply of much lower ammonia levels, albeit slower than maximum, and that is how we do fish and fishless cycles.

But the bacteria do live on "trace" amounts of ammonia. Obviously, less than the 0.25 ppm we can test for. While I have not explicitly researched nitrosomas or nitrobacter in the lab, living organisms are not typically on/off things, but have a range of metabolic activity, and thus a range of ammonia and nitrite metabloizing capacity. This is temperature, pH, and oxygen dependent at least, and I would think nutrient availability as well. Not expecting magic here, just to follow the ways other bacteria behave. Personal experience makes me think that ammonia availability in the inhabited tank is rather variable, depending on fish activity and feeding, decaying stuff and such. Unlike your big square test tube when doing a fishless cycle. Not seeing ammonia and nitrite pop up after fleeting changes in the inhabited tank makes me think the mature biofilter is capable of reacting to the varying loads we put on it, which is a darn good thing for us. Only explanation I have for this is that the bacteria can increase metabolism when the oportunity presents, since they certainly can't double fast enough to deal with transient changes. Hence the conclusion that the bacterial colony are many bacteria operating below maximum level rather than fewer bacteria operating at maximum. And even if they can only double once a day, that represents a significant response ability for a mature biofilter of many bacteria if a sustained change in ammonia load presents itself.

I am a wierdo, and actually enjoy reading about the nitrifying bacteria as much as the other inhabitants in my tank, as long as its not just a "journal of bugs" article published to keep the university types going -- it has to have some relevance to aquariums! Should you find your links and articles, perhaps we can swap some sources? I haven't searched any out in over a year myself.

Will do. These conversations are the ones I look forward to on this forum. And like you I'm a sucker for the nitrifying bacteria information, as long as its relevant to what we are doing!

 

[garth7]

Wow, I didnt mean to stirr up some controversey but conversations like this is very useful to our community here. Ideas and experiences like the above ones are great!!!! I wish I could go into the store everyday after work to get newbies but I have to wait till pay day! I usually take the slow and conservative approach because of this.