Cycling a tank - is it necessary

[pip walters]

Hi people.

I would like to give my opinion on cycling a tank, based on my 30 years working with fish. Please let me know your thoughts.

The fishless cycle seems to be the most confusing and conflicting among aquarists and is something that was unheard of when I first began my fishy journey, so I would like to ask one or two questions and maybe share my personal experiences with the nitrogen cycle.

Firstly, the fishless cycle.
What I have read about this seems rather vague to me. Are you trying to get the filter bacteria established enough to add a full stocking of fish at once? If so, then you need to know exactly how much ammonia your stocking of fish is going to produce on a daily basis and for that, you need to know what weight of food they are going to eat each day. The ammonia produced will be a percentage of food consumed. Once you know this, then you can add the correct weight of ammonia each day until the bacteria multiply enough to keep the ammonia at an acceptable level constantly.

To know how much weight of food your fish need, you need to know what percentage of bodyweight in food they need each day - How many of us weigh our fish and calculate the daily requirements?

If you are trying to establish enough bacteria to start adding fish, then you are wasting your time. You can buy bacteria in a bottle - it appeared many moons ago when I was in pet retail. The manafacturers developed it to help us mature a tank more quickly, yet here we are being told it takes 3 to 6 weeks to cycle a tank... have we gone backwards??

Add this bacteria to your tank, it will double its population every 20 minutes and you can add a fish or two, depending on species, size of tank etc the next day... the fish will produce only small amounts of ammonia until you feed. Feed tiny amounts little and often and the fish produce tiny amounts of ammonia little and often, rather than large amounts in a short time, which causes 'spikes'.

Nitrite
This will build up far more gradually in your tank than you may think. As small amounts of ammonia are produced, your bacteria will steadily break it down into nitrite and this will increase steadily until this is enough other bacteria develop to break it down into nitrate.

Here's something you may not believe... fish can tolerate nitrite build up! I once raised carp fry in water that measured 8ppm nitrite (on a high quality scientific test kit). Common consensus tells me those fry should have been dead. Most people I know in the fish farming industry do not worry about nitrite! The fry were feeding for 12 hours per day and growing normally.

How many of you measure dissolved oxygen in your tank? In a closed system, oxygen is, in my experience, by far the biggest limiting factor, but we rarely monitor it in an aquarium.

Discuss.

 

[20cc]

why would you submit a living thing to a toxic environment?

 

[GodFan]

Hi people.

I would like to give my opinion on cycling a tank, based on my 30 years working with fish. Please let me know your thoughts.

The fishless cycle seems to be the most confusing and conflicting among aquarists and is something that was unheard of when I first began my fishy journey, so I would like to ask one or two questions and maybe share my personal experiences with the nitrogen cycle.

Firstly, the fishless cycle.
What I have read about this seems rather vague to me. Are you trying to get the filter bacteria established enough to add a full stocking of fish at once? If so, then you need to know exactly how much ammonia your stocking of fish is going to produce on a daily basis and for that, you need to know what weight of food they are going to eat each day. The ammonia produced will be a percentage of food consumed. Once you know this, then you can add the correct weight of ammonia each day until the bacteria multiply enough to keep the ammonia at an acceptable level constantly.

To know how much weight of food your fish need, you need to know what percentage of bodyweight in food they need each day - How many of us weigh our fish and calculate the daily requirements?

If you are trying to establish enough bacteria to start adding fish, then you are wasting your time. You can buy bacteria in a bottle - it appeared many moons ago when I was in pet retail. The manafacturers developed it to help us mature a tank more quickly, yet here we are being told it takes 3 to 6 weeks to cycle a tank... have we gone backwards??

Add this bacteria to your tank, it will double its population every 20 minutes and you can add a fish or two, depending on species, size of tank etc the next day... the fish will produce only small amounts of ammonia until you feed. Feed tiny amounts little and often and the fish produce tiny amounts of ammonia little and often, rather than large amounts in a short time, which causes 'spikes'.

Nitrite
This will build up far more gradually in your tank than you may think. As small amounts of ammonia are produced, your bacteria will steadily break it down into nitrite and this will increase steadily until this is enough other bacteria develop to break it down into nitrate.

Here's something you may not believe... fish can tolerate nitrite build up! I once raised carp fry in water that measured 8ppm nitrite (on a high quality scientific test kit). Common consensus tells me those fry should have been dead. Most people I know in the fish farming industry do not worry about nitrite! The fry were feeding for 12 hours per day and growing normally.

How many of you measure dissolved oxygen in your tank? In a closed system, oxygen is, in my experience, by far the biggest limiting factor, but we rarely monitor it in an aquarium.

Discuss.

Cycling is necessary but fishless cycling is not. Bottled bacteria is still controversial.
Cycling is not always necessary if you have tons of plants though.

 

[sodbuster95]

I think you may be overthinking the fishless cycle. The point - at least in my mind - is to establish a friendly environment into which one may introduce fish without risking the lives of the fish. A "humane" method, if you will. Is it necessary? No. One can do a fish-in cycle and still be humane, but one can hardly argue that the fish-in method requires a great deal more work to ensure that the levels of toxicity remain tolerable to the fish. Which is certainly not to say that it cannot be done. It merely is recognition that it requires greater work and commitment.

As to the amount of ammonia...I dose the tank to about 4 PPM of ammonia and simply wait. Sometimes it takes a week or two, sometimes longer. But there is little to no work involved. Once the ammonia levels decrease, simply re-dose ammonia to keep it at or around 4 PPM. Nitrite then begins to form and you continue to dose ammonia to keep the cycle going. Once nitrites go to zero and nitrates appear, the cycle is complete. No fish harmed, and you have a fully cycled tank ready for stocking. You can certainly make it more complicated by trying to figure out exact amounts of ammonia for your intended stocking level, but that's not necessary.

As to the bacteria in a bottle, some might work, some don't. I've never had any luck with them, personally.

 

[Thumper828]

I think you may be overthinking the fishless cycle. The point - at least in my mind - is to establish a friendly environment into which one may introduce fish without risking the lives of the fish. A "humane" method, if you will. Is it necessary? No. One can do a fish-in cycle and still be humane, but one can hardly argue that the fish-in method requires a great deal more work to ensure that the levels of toxicity remain tolerable to the fish. Which is certainly not to say that it cannot be done. It merely is recognition that it requires greater work and commitment.

As to the amount of ammonia...I dose the tank to about 4 PPM of ammonia and simply wait. Sometimes it takes a week or two, sometimes longer. But there is little to no work involved. Once the ammonia levels decrease, simply re-dose ammonia to keep it at or around 4 PPM. Nitrite then begins to form and you continue to dose ammonia to keep the cycle going. Once nitrites go to zero and nitrates appear, the cycle is complete. No fish harmed, and you have a fully cycled tank ready for stocking. You can certainly make it more complicated by trying to figure out exact amounts of ammonia for your intended stocking level, but that's not necessary.

As to the bacteria in a bottle, some might work, some don't. I've never had any luck with them, personally.

I agree with this.

 

[Masha]

From what I've seen: fish-in can be fine, but probably more suited to experienced fish-keepers.

For beginners, fish-less is less stressful, less work, and if they mess up, nothing dies.

 

[Mebbid]

I agree that you are overthinking this a lot. The goal of a fishless cycle isn't to add an entire stocking at once but instead is to get the tank safe for fish so they don't have to go through the stress of heightened ammonia levels.

The 4ppm of ammonia that is dosed in a fishless cycle is more than enough ammonia for a fully stocked tank to produce. Looking at it in a big picture point of view if I'm not mistaken each 1ppm of ammonia converts to about 4ppm of nitrate. If you are putting enough fish into the tank to generate that amount of ammonia you would be getting over 100ppm of nitrate production weekly which is a seriously overstocked tank. The fishless cycling is supposed to be done in such a way that it builds up more bacteria than a tank needs to support its entire stocking.

The bottled bacteria is indeed controversial. I see more people having no success with it than I see people getting good results, myself included.

As for the nitrite with the carp without knowing the other parameters I would imagine that the success with raising carp in high concentrations of nitrites stems from them being a hardy fish when compared to most aquarium fish.

 

[Delapool]

How many of you measure dissolved oxygen in your tank? In a closed system, oxygen is, in my experience, by far the biggest limiting factor, but we rarely monitor it in an aquarium.

Discuss.

Hi, in a sense I do monitor this if the fish are gasping at surface. However I'm reacting to any problems, it would be better if I had an O2 monitor and a bottle set to go before the problem arose ie a prevention system. IMO the fish-less cycling is same issue, the bb is established to prevent any problems. I've also seen articles that wonder if the dosing to 4ppm creates a larger than needed bb population but I guess it should be bullet proof. It would be interesting to know of any issues a too large bb population may create - to date I haven't seen anything on this. Interesting topic.

 

[Blitz]

People can also survive in a ghetto, in the jungle, in a desert, in cold regions, in extreme temps up and down, on very little food and water, to sustain life, but that does not mean it's the best environment. Keep in mind, that the majority of people doing this are doing it as hobbyists, and their fish population are pets, in an environment, meant to mimic the fish's natural environment, but also bring a beautiful focal point to their home. Whether they are in it for Aquascapes, emulating an ocean scene, or river, tropics, the majority of fish keepers are not doing it to raise fish for farming, although that sometimes becomes an evolution.

The topic of this forum, is Aquarium Advise, and although I see many varied topics relating to all facets of fish keeping, I think one of the most talked about is the cycle. I can't tell you how many times, I read posts by new members have no clue about a cycle, usually shortly after they introduce themselves, quickly followed up with their problems, they are then bombarded with responses pointing them in the direction to how to cycle a tank. Although it may seem harsh to new comers, I think they realize quickly, that the members here are serious about acclimating new life to a new aquarium environment, that it's something that should be well thought out and not just done on a whim.

I think a topic titled like this is confusing to prospective new fish keepers or people who never really join the forum and just read, although it may be intended for conversation, some might think, hey, this guy seems to know what he's talking about because he uses a "high quality scientific test kit". "I don't need to cycle my tank". The fact is, regardless of fishin or fishless cycle, it is proven, that it's necessary, to introduce fish the safest and with the least amount of stress.

I too began around the same time you did, 30 years ago, and there was not the information available that there is today, Things evolve in this industry/hobby, some are debatable as to their validity, or actual benefit, for me, and my investment, This is not one of them.

 

[pip walters]

Cycling is necessary but fishless cycling is not. Bottled bacteria is still controversial.
Cycling is not always necessary if you have tons of plants though.

Establishing a culture of nitrifying bacteria is essential, I would say

Most of the products available work at different rates depending on whether the bacteria is 'dormant (as in the powdered cultures) or live and ready to go. My favourites have been very successful for me in the past - Hagen Cycle and JBL Denitrol

 

[pip walters]

why would you submit a living thing to a toxic environment?

I wouldn't. Toxicity is subject to a range of differing conditions, such as pH, temperature and dissolved oxygen content.

 

[pip walters]

I think you may be overthinking the fishless cycle. The point - at least in my mind - is to establish a friendly environment into which one may introduce fish without risking the lives of the fish. A "humane" method, if you will. Is it necessary? No. One can do a fish-in cycle and still be humane, but one can hardly argue that the fish-in method requires a great deal more work to ensure that the levels of toxicity remain tolerable to the fish. Which is certainly not to say that it cannot be done. It merely is recognition that it requires greater work and commitment.

As to the amount of ammonia...I dose the tank to about 4 PPM of ammonia and simply wait. Sometimes it takes a week or two, sometimes longer. But there is little to no work involved. Once the ammonia levels decrease, simply re-dose ammonia to keep it at or around 4 PPM. Nitrite then begins to form and you continue to dose ammonia to keep the cycle going. Once nitrites go to zero and nitrates appear, the cycle is complete. No fish harmed, and you have a fully cycled tank ready for stocking. You can certainly make it more complicated by trying to figure out exact amounts of ammonia for your intended stocking level, but that's not necessary.

As to the bacteria in a bottle, some might work, some don't. I've never had any luck with them, personally.

I'm not over-thinking, just trying to apply what I know and have experienced with the nitrogen cycle - too few fishkeepers don't think enough about this subject, hence many, many misunderstandings about 'cycling' a tank. This industry is based on lack of knowledge, hard as that is to take. Fish die through a lack of understanding and more are supplied!

You say that once nitrite goes to 0 and nitrates appear, you can add fish. How many fish? What if those fish aren't producing 4ppm ammonia with the same regularity with which you were adding it manually?

What happens is, the BB die off through lack of food and numbers of BB are reduced to cope with just the ammonia excreted by the fish. A large die-off of bacteria in the filter can cause anaerobic conditions where de-nitrification takes place and nitrite is converted back to ammoniacal nitrogen.

Of course you can do a fish-in cycle and be humane - mother nature does it all the time and aquarists have been doing it for decades. It is a gradual process. Adding one or two fish to a large aquarium and feeding small but regular amounts whilst adding a supply of BB (be it from a bottle or seeded from an established filter), will allow a naturally gradual increase in nitrifying bilogical organisms.

 

[pip walters]

From what I've seen: fish-in can be fine, but probably more suited to experienced fish-keepers.

For beginners, fish-less is less stressful, less work, and if they mess up, nothing dies.

I understand what you are saying, but I would say that the fish-in cycle is probably more suited to more patient fishkeepers!

With the fish-less cycle, how can you mess up? If you add too much ammonia, the bacteria will eventually multiply to the numbers needed to convert that ammonia - it will jut take longer than required.

 

[Delapool]

Establishing a culture of nitrifying bacteria is essential, I would say

Most of the products available work at different rates depending on whether the bacteria is 'dormant (as in the powdered cultures) or live and ready to go. My favourites have been very successful for me in the past - Hagen Cycle and JBL Denitrol

Out of interest, have you done any test work on this? I was thinking of setting up some test tanks next winter. The problem I'm having is that from reading it seems that transport, heat, storage conditions plus shelf life may mean that results can't be duplicated. I've only seen the liquid product here.

 

[pip walters]

Hi, in a sense I do monitor this if the fish are gasping at surface. However I'm reacting to any problems, it would be better if I had an O2 monitor and a bottle set to go before the problem arose ie a prevention system. IMO the fish-less cycling is same issue, the bb is established to prevent any problems. I've also seen articles that wonder if the dosing to 4ppm creates a larger than needed bb population but I guess it should be bullet proof. It would be interesting to know of any issues a too large bb population may create - to date I haven't seen anything on this. Interesting topic.

Thank you, a more reasoned and considered reply than some. I have to be honest, I am not sure where this 4ppm comes from?? This, to me, is misleading as it suggests that, no matter how many fish you have, they will produce no more than 4ppm. Also, I am assuming from some comments here, that this is a weekly dose? Do we need to continue adding some ammonia if we only add one neon tetra after fish-less cycling a 40 gallon tank?

If there are too many bacteria for the amount of ammonia produced, the excess bacteria will eventually die off (and produce ammonia as they decompose - producing temporary food for the remaining bacteria). This is why I see the fish-less cycle as a waste of time - in the form most talk about anyway, because how do you know if the fish you add are going to produce the same 4ppm at the same regularity.

This is why a fishless cycle should be based on the amount of food the fish are going to be eating once introduced. I suppose what I am saying is, you can do a fishless cycle, but only for a fixed weight of fish.

And to the subject of oxygen, nitrification is also reliant on the correct amount of available oxygen - the closer the oxygen level is to 100%, the more efficient the bacteria will be in converting nitrogen.

 

[pip walters]

Out of interest, have you done any test work on this? I was thinking of setting up some test tanks next winter. The problem I'm having is that from reading it seems that transport, heat, storage conditions plus shelf life may mean that results can't be duplicated. I've only seen the liquid product here.

I have questioned how the bacteria lives in the bottles myself to be honest and I am going to contradict some of my own comments by saying this, because I have said that if there is not enough ammonia to support a population of BB, then some will die off until a population is established to cope with the ammonia that is present. The fact is, many bacteria will go into a kind of dormancy for a certain length of time, before actually dying off, or 're-animating if ammonia becomes available again. I would suggest that the bottled BB has had the environment manipulated so it remains viable for longer periods - I will be attempting to research this in the near future, although I'm not sure manafacturers are going to be very forthcoming with their methods!

I used ammonia to cycle the systems in which I used to grow young carp, koi, etc by adding enough ammonium nitrate per day to replicate the amount that would be produced by the weight of feed that would be consumed by the biomass of fish I intended loading into the system.

It is important to also know you have enough oxygen in the system if you are going to do any testing. Our fish farming systems used injection of pure oxygen to keep dissolved oxygen as close to 100% as possible at all times. Heavy aeration to gas of carbon dioxide is also important

 

[Caliban07]

I have posted quite regularly on here that if I was ever to do a fish less cycle, I would try to replicate a fish in cycle. I would add small doses as if I'd just added 3 neons and gradually build up to 4ppm. Again I can't really say where 4ppm has come from except that I have read it on here. Your never really going to be able to calculate how much ammonia fish produce as ammonia comes from other things than just food. As you said fish respiration for example. Respiration of a stressed fish will be different, respiration at night will be less than when swimming around.

The problem I see with dosing 4ppm ammonia straight of the bat during a fish less cycle is bb competition. By the time heterotrophic bacteria has colonised x amount of surface area, ammonia nitrifying bacteria will start to feed and grow and colonise a surface area equal to 4ppm of ammonia. Does this leave enough surface area for nitrobacter? We know they are slow reproducers as it. Is this the reason why countless people claim that their cycle has 'stalled' and nitrites go through the roof ?

Personally, I believe fish in cycling is less stressful if you follow the rules. Which is basically stock slowly and feed sensibly. Using suitable fish. As long as your tap water doesn't contain high levels of ammonia. There should be no reason why ammonia should get high enough to warrant a water change. It shouldn't have enough time. The bb should be growing in proportion to the food that is available without toxins getting to high to harm the fish.

For example Putting 3 plecs in a 10 gallon tank that are fed on algae wafers isn't going to work. Toxins in this case will obviously rise quicker than they can be consumed.

 

[DragonFish71]

As a person who's first concern is the health of my fish, I will admit my preferred method is the fish-in cycle with a bottle of API Quick Start. I've tried a few others, and so far, 6 tanks in (not all mine), I'm liking the API better.

Yes, OH MY GOSH, a mod admits to fish-in cycling!

Only because I monitor the tank constantly and my husband and I are ready to do water changes before it becomes a hazard to the fish.

I have tried fish-less with the ammonia, way too much hassle for me, and I've done a frozen shrimp as an ammonia source. Which, other than being a boring waste of a tank while waiting for it to cycle, is a good way to go.

To be honest, I went back to fish-in because of being bored with watching an empty tank and because I know we are a responsible couple who will monitor the water conditions so that the fish remain healthy. We only start out with a few certain fish, which end up re-homed in a specific tank, where they live happy, long lives.

For those curious, 18 tanks now (one new one in week 3 of fish-in cycle)

As for the science of it, if your tank, once populated, has 4ppm of ammonia, you have a HUGE problem.

 

[pip walters]

Where on earth has this 4ppm come from? I just read an article that attempts to explain how to do a fish-less cycle by maintaining ammonia at 4ppm per day until the BB develop enough to convert all that ammonia to 0.

Firstly, conversion isn't instant, so if you test after an hour, you are unlikely to have 0 ammonia. Secondly - that is a hell of a lot of ammonia!

Ok here goes with a calculation

Ammonia at 4ppm in 100 litres = 0.4g of ammonia.

For fish to produce 0.4g of ammonia per day, you would need to be feeding just under 134g of food PER DAY.

Lets take carp as an example (as they have a high food conversion rate - 100% in the right conditions). 13.4g of food is enough to maintain the health of (but not to grow) a biomass of 1.34kg of carp (i.e. 1% of their bodyweight in food per day). How many of us would keep a carp 1 ounce short of 3lb in a 100 litre tank? It can be done... easily, but as aquarists, we wouldnt would we?

So why are we dosing ammonia at a rate vastly higher than will ever be maintained by a recommended stocking of fish? If we wanted to do a fish'less cycle on a 15 gallon tank in order to stock a full recommended stocking of, say neon tetras, we would have to spend a lot of money on a very accurate miligram scale!

No wonder the fish-less method takes up to 8 weeks or more! Those poor BB!!

 

[pip walters]

I have posted quite regularly on here that if I was ever to do a fish less cycle, I would try to replicate a fish in cycle. I would add small doses as if I'd just added 3 neons and gradually build up to 4ppm. Again I can't really say where 4ppm has come from except that I have read it on here. Your never really going to be able to calculate how much ammonia fish produce as ammonia comes from other things than just food. As you said fish respiration for example. Respiration of a stressed fish will be different, respiration at night will be less than when swimming around.

The problem I see with dosing 4ppm ammonia straight of the bat during a fish less cycle is bb competition. By the time heterotrophic bacteria has colonised x amount of surface area, ammonia nitrifying bacteria will start to feed and grow and colonise a surface area equal to 4ppm of ammonia. Does this leave enough surface area for nitrobacter? We know they are slow reproducers as it. Is this the reason why countless people claim that their cycle has 'stalled' and nitrites go through the roof ?

Personally, I believe fish in cycling is less stressful if you follow the rules. Which is basically stock slowly and feed sensibly. Using suitable fish. As long as your tap water doesn't contain high levels of ammonia. There should be no reason why ammonia should get high enough to warrant a water change. It shouldn't have enough time. The bb should be growing in proportion to the food that is available without toxins getting to high to harm the fish.

For example Putting 3 plecs in a 10 gallon tank that are fed on algae wafers isn't going to work. Toxins in this case will obviously rise quicker than they can be consumed.

If you can afford the equipment sensitive enough to measure the amount of ammonia discharged by three neons, then I want to be your best friend