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Fish-in Cycling

Discussion in 'New to the Hobby Questions and Answers' started by rabbut, Dec 27, 2007.

  1. rabbut

    rabbut I don't bite, all that often...

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    Fish in cycling, a beginner’s guide.

    This is the process of cycling a tank using fish. Most people on the forum advise against this, but since so many of us fall into the trap of purchasing fish a few days after setting up the tank on their LFS’s advise, I thought I would write this guide. If you have not yet added any fish, I would strongly advise you to look at this thread, here to fishless cycle your tank. This is far more humane for you fish.

    What is cycling?

    This is the process of building up a colony of filter bacteria, to break down your fishes waste. Your filter will not function correctly until the cycle has finished, and unless care is taken, your fish may get poisoned to death as a result :sad: It is important to maintain this colony of bacteria at all times, as your fishes health depends upon a correctly working filter. Please read-up on filter media, [topic="139488"]here[/topic] and also general maintenance, [topic="171045"]here[/topic]
    In a cycled tank, ammonia from fish waste is broken down into nitrite, by one set of bacteria. Another type of bacteria then breaks down nitrite into nitrate, the usual bi-product of your filters.

    The term “Cycling” came about, as this is the process of establishing the nitrogen cycle in your aquarium. Fish produce waste. Some in the form of ammonia and other waste in other forms, which are converted to ammonia. There is one set of bacteria that break ammonia down into nitrite. Then another set of bacteria break this down into nitrate. In nature another set of bacteria would break nitrate down into nitrogen gas, and oxygen. This does sometimes occur in the aquarium, but filters are designed to stop this. This is because the by-product of the nitrate breakdown phase is Hydrogen Sulphide, which is also toxic. If enough Hydrogen Sulphide gets released, it can crash a tank (indirectly) by removing all the Oxygen from the water. This is why a tank ideally only contains bacteria to break down ammonia and nitrite. :good:

    How to cycle with fish in your tank

    As above, we are trying to build up a colony of bacteria, to remove your fish’s waste. To do this with fish in the tank, however, we will be exposing them to poisons, mainly ammonia and nitrite (note spelling), which will eventually be converted into nitrate, the by-product of your filter. It is important for your fish’s health, that the ammonia and nitrite levels remain low. These two chemicals are dangerous long-term at any level detectable, but start showing short-term damage above 0.25mg/l, or 0.25ppm. Invest in a test kit, to monitor these readings. Nitrate is also toxic in large amounts. 50ppm should be the highest you allow nitrate to go, but fish will adapt to values up to 100ppm. Liquid drop tests are the most accurate, and dip strips are notoriously inaccurate. I use the Tetra range of test kits, but many on here recommend API. An API master kit will cost around £25, and Tetra are more expensive. API is not available to me however, and this is why I use Tetra.
    To keep the ammonia and nitrite at an acceptable level, we must water test at least twice a day, and carry out 50% water changes as appropriate, i.e. if any reading for ammonia or nitrite comes out above 0.25. Testing needs to be done regularly, as conditions in a cycling tank change quickly. It isn't uncommon to go from ammonia only, into a phase where ammonia is undetectable, and nitrite is through the roof with this type of cycling. To keep our fish alive, we must monitor values of ammonia and nitrite carefully, or we may seriously damage our new pets. All water added to a tank must be de-chlorinated, or the new water may kill either the fish or the filter media’s bacteria. Tap water conditioner is used for de-chlorinating new water. There are many brands out there, mostly doing the same job. Check they remove chlorine, chloramines and heavy metals.
    A pH below 6 will dramatically slow the cycle. If it drops below this, carry out a water change. pH is a measure of how acid or alkaline water is, and is held stable by minerals dissolved in your water. A stable pH is more important than one in the ideal range, unless your pH repeatedly drops below 6. If the pH repeatedly drops, you are short of minerals in your tap water. You can add coral sand or coral gravel to the filter or substrate to up the hardness of your water, and raise the pH. This will hold the pH stable at this new value, unlike many other chemicals. Make sure you add this slowly, until the pH reaches 7. Adding too fast will stress your fish.
    Once levels for ammonia and nitrite have been 0 and nitrate has been rising, you are cycled for that fish load, and you are ready for a few more fish, space allowing. Remember never to add enough fish to double the numbers in a 24 hour time period. This is because it will take time for the existing bacteria to multiply sufficiently to allow for the increased load. Always test the water before adding fish, and also test around 12hours after, to ensure all levels are at a safe value. Check all levels daily for a week after adding fish, to ensure the filters are still coping :good: Once cycled, and all levels for ammonia and nitrite are nil for a week, and nitrate is steadily rising, get yourself into the usual weekly maintenance routine, as described in the articles linked above.

    Any suggestions for improvement welcome
    Rabbut
     
  2. radioman

    radioman Member

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    I think this is helpful for those who do not want to return fish.
     
  3. rabbut

    rabbut I don't bite, all that often...

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    glad to hear you approve. Any points for improvement anyone?

    All the best
    Rabbut
     
  4. dthoffsett

    dthoffsett I'm a girl . . . yup, definitely a girl. =)
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    Just thought I'd point out that unless you have live plants or are using RO water, there will almost always be a detectable level of nitrate.

    Other than that, sound pretty good. :good:
     
  5. rabbut

    rabbut I don't bite, all that often...

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    Thanks for that, a little oversight on my part :blush: Will rectify :good:

    All the best
    Rabbut
     
  6. Tobigara

    Tobigara Member

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    i can't think of anything else to add. well done, rabbut! :good: how do we get this pinned?
     
  7. rabbut

    rabbut I don't bite, all that often...

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    Thanks Tobigara. I was just writing this to save me some time typing out multiple times in cycling topics, but if you recon its pinworthy, then feel free to recomend it :good:

    Rabbut
     
  8. backtotropical

    backtotropical Retired Mod
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    Good thread Rabbut, and i'm all for pinning it. A good fish-in cycling guide is definitely something that the forum really needs.

    If i may suggest, i think mentioning ammonium is unnecessary and confusing. As the ratio of ammonia to ammonium depends on PH and temperature, and ammonium is actually not toxic to fish (at least not in the levels found in our tanks), i would suggest that keeping it simple is the key (as this thread is really aimed at new hobbyists) and that only ammonia, nitrite and nitrate need be mentioned in this respect. In addition to this you give a good indication of what the desirable readings are for ammonia and nitrite, but not nitrate.

    You state that all tank water should be dechlorinated, but do not elaborate on how to do this. (Beginners may not know)

    You briefly mention PH, but kind of skim over the issue. I would suggest that you should include a section to relay the importance of a stable PH and how to achieve this.

    Also you mention test kits, but do not recommend a test kit for nitrate. I suggest that tests for ammonia, nitrite, nitrate and PH are useful/necessary for the beginner.

    Sorry if this seems picky, i'm trying to imagine i don't know anything about the hobby and what i might need.

    Good work, i'm going to recommend pinning if nobody else has. :good:

    BTT
     
  9. rabbut

    rabbut I don't bite, all that often...

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    Thanks BTT. Its been a while since I was a beginner, so I forget that things that seem obvious to us more experienced members, is not always so when you are starting out. I will modify the first post appropriately, having taken your words of advise onboard :good:

    All the best
    Rabbut
     
  10. andywg

    andywg Bored into leaving

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    Should there really be a section on pH? I know it is easier to tell people about it, but the science found by bignose indicates that pH swings are not a problem for fish, but hardness swings are.

    I don't think we really want to go myth debunking in a guide, but do we want to give out potentially incorrect information?

    Perhaps if you state that tanks with a stable pH and other parameters do better, or something?

    /me is unsure of how to remedy this.
     
  11. rabbut

    rabbut I don't bite, all that often...

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    A valid point andywg. I assume you are refuring to bignoses post about aclimation here? If so, wasn't his research indicating that changes in hardness could effect the ability of the fish to remove toxins form their body, while they adjusted to the new conditions? If this is so, then it probibly would be best to state that stability is more important, and indicate that if the pH crashes, it is best to do a waterchange, but adding the new water over a period of time, rather than in one go? Presumably there would be a significan difference in KH if the pH has crashed, to the new water being added?

    All the best
    Rabbut
     
  12. rabbut

    rabbut I don't bite, all that often...

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    Anyone? Members who have just read this, did you find it easy enough to understand?

    All the best
    Rabbut
     
  13. backtotropical

    backtotropical Retired Mod
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    Spot the mistake........................................

    It's reading much better Rabbut. I don't know if i would recommend using powder buffers to beginners though. I think that's asking for trouble. I would rather recommend that a handful of coral sand or coral gravel is mixed into the substrate as appropriate, as this would hold the conditions of the tank more stable than powder based solutions which need to be added regularly.

    Cheers

    BTT
     
  14. backtotropical

    backtotropical Retired Mod
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    Just spotted this too. I think this should read 'many'.

    :good:
     
  15. rabbut

    rabbut I don't bite, all that often...

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    woops :blush: thanks btt


    Another good point btt. I forget how quickly these powdered buffers swing the pH too, so have heeded your advise and changed the bit about raising hardness accordingly :good:

    All the best
    Rabbut
     

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