Help Cycling new 125 gallon freshwater tank

[fisherman26]

I just started a 125 gallon tank i put some meadia from my 10g into it and also got 15 zebra danios to cycle with. Is that enough fish to start a cycle with and how long before i start to see readings? I have a acuaclear 110 and 70 and air pump and 2 300w heaters set at 78 deg. Thanks for your help.

 

[OhNeil1969]

First let me say that anything I say is my HUMBLE opinion. Now for my opinions. That's a really big tank to cycle with danios. I will say that from my experience with this forum that the preferred way of cycling is fishless. Where did you get all those danios from? Can you return them? I know danios are a hardy species and can usually withstand the rigors of an uncycled tank, but you're still putting them in harms way. Try cycling with ammonia. There are plenty of threads in this site that provide info on fishless cycling. I'm cycling a 60 gallon tank without fish as we speak.

 

[noob2saltH20]

You will know when your tank is in its cycle by checking your ammonia and nitrites. When your tank starts to cycle your ammonia will spike when you do water tests (ie a high reading on the ammonia chart) next your trites will start to raise. A cycle usually takes about 2 to 4 weeks to cycle. Once your tank has cycled do a 10 to 20 percent water change and you will be good. 15 danios seems a bit much to start with but that's just me. I would say at the vary least a few days u should see reading esp. Since u have your danios in there. Hope this helps some

 

[fisherman26]

I got the danios at the pet shop for 10 bucks and they said i could bring them back when the tank cycles. Its been going with fish in it for 2 days and i dont have any ammonia or other readings yet. Will the filter from the 10 gallon tank help it cycle faster? Do you think i have enough filtration for the tank? and what should i stock in it? Ive got a common pleco that im going to put in it once it cycles. I was thinking 5 bala sharks, 6 corys, 5 dwarf gorominis and some tetras and maybe some kind of barbs. Would those fish get along? What would do best together? Thanks guys im still new to this.

 

[OhNeil1969]

I think your local pet shop is trying to take advantage of you. They're probably counting on your fish being dead before the tank cycles. I have to admit I've never heard of a LFS taking fish back after that length of time (cycling a tank will take at a minimum 3 weeks if you are lucky). The filter will help it cycle faster; it may even have enough bacteria to keep your danios alive. I'm really not sure. The one concern I have has to do with your plans for the tank after cycling. The bacteria culture you will grow will only be enough to deal with the danios. The fish you are talking about putting in your tank will definitely put a strain on your bacteria colony. That's why I didn't think 15 danios could properly cycle a 125 gallon tank. Bacteria will only grow to the amount that the ammonia present will support. The increased bioload you are looking at with the fish you are interested in will overpower your bacteria colony. Now if you were to slowly introduce those fish to your tank over an extended period of time you might be able to get away with it (you should be doing that anyway). I'm not really sure how compatible those fish you listed are with your tank, but I can recommend this site: AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor. It will help find out whether or not your selection of fish will work. It will even tell you if you have enough filtration. As I was told on this site recently, aqadvisor is conservative, but that's a good thing in my opinion.

 

[noob2saltH20]

Yeah your lfs is weird. I never tell people to cycle their tank with fish unless its a commit gold fish. As far as the fish I would try to stick with the same species of fish. I'm not a fan of plecos they tend to double their waste output then let's say a chinese alge eater I would recommend that instead of a pleco

 

[fisherman26]

So far ive got 15 danios and a goldfish and its been a week and still no ammonia readings. Is there not enough fish in it to build up ammonia or is the old filter media bacteria using it and im not getting a reading?

 

[OhNeil1969]

So far ive got 15 danios and a goldfish and its been a week and still no ammonia readings. Is there not enough fish in it to build up ammonia or is the old filter media bacteria using it and im not getting a reading?

Ultimately, a 0 ammonia reading is good. I know you are concerned because you're trying to cycle a new tank. What are your readings for nitrItes and nitrAtes? If the nitrite reading is high then you are in what I call the second stage of cycling. The pattern is this:
1) fish produce ammonia
2) bacteria start to become present and consume that ammonia - your readings for ammonia will start to go down eventually to zero in an established tank
3) those bacteria create nitrItes when consuming ammonia - you'll start to see a rise in your nitrIte readings
4) a second form of bacteria will show up and start to consume the nitrItes - you'll start to see the nitrite reading go down to zero in an established tank
5) after the nitrItes are consumed you'll start to see a rise in the reading of nitrAtes. That's the final byproduct of the cycle you'll see. You'll want to keep the nitrAtes at or below 20 ppm. Your best defense against high nitrAtes will be weekly PWC's.
I recommend you start testing all 3 water parameters and keep a log of your results. As I said, you'll see the ammonia start to go to zero. You'll then see the nitrItes rise for a while before starting to fall back to zero. In the end you will see a rise in nitrAtes that you will control with water changes.

Hope this helps!

 

[fisherman26]

I know zero ammonia is good but the tank has been running a week and with all the fish in it i havent even had any ammonia or nitrites. Im just wondering if i need more fish to start the cycle or does it just take a week or more for ammonia to show up ive tested the water every day with my freshwater master test kit. also the other question could the filter media out of my 10 gallon tank just make it do like a instant cycle to where i didnt get any readings. Thanks oneal1969.

 

[OhNeil1969]

I know zero ammonia is good but the tank has been running a week and with all the fish in it i havent even had any ammonia or nitrites. Im just wondering if i need more fish to start the cycle or does it just take a week or more for ammonia to show up ive tested the water every day with my freshwater master test kit. also the other question could the filter media out of my 10 gallon tank just make it do like a instant cycle to where i didnt get any readings. Thanks oneal1969.

Your problem seems to go back to what I originally thought would make cycling this tank difficult. 15 danios in a 125 gallon tank are going to have a hard time cycling this tank. When performing a fishless cycle people aim for anywhere between 2 and 5 ppm of ammonia. That level of ammonia is of course toxic for fish but allows for a bacteria colony large enough for your tank to grow. The impact those danios have on your entire tank will be minimal. It may be as you suspect that the bacteria in your seeded filter is enough for the fish currently in the tank. If that's the case then you'll probably have to wait a few weeks to see nitrates (not nitrites).

What type of tank did the filter come from? How many fish were in that tank? Remember, bacteria will only grow to the level that the ammonia present will support. Without that ammonia the bacteria will eventually die of starvation. Furthermore, if there is already enough bacteria present to handle the ammonia produced by the danios, then new bacteria will not grow.

 

[fisherman26]

The filter media came from a 10 gallon tank with a 3inch comet goldfish and a common pleco. I placed the goldfish in the 125 to try and get a ammonia reading but so far hasnt showed up on the test. So if there is enough bacteria for the danios and goldfish would i be ok to put the pleco in there as well or should i wait it out to see if i get any ammonia before putting him in the 125?

 

[OhNeil1969]

I'd be worried about putting a 3 inch goldfish with the zebra danios. Goldfish and tropical fish are not the best tank mates. For one, they thrive in different water conditions (goldfish like colder water, higher pH). The other thing is that the goldfish may start to look at the danios as a food source. If you want to put the pleco in there you can. Just be careful. I'd wait for a few weeks of water testing with the danios present. When you see 0 ammonia, 0 nitrites and about 20 ppm of nitrates then you'll have a tank that is safe for the danios. At that point I would add the pleco and start monitoring the water again. The pleco should give you an ammonia spike within a week of it's introduction (maybe longer). It won't be a huge spike but one that can be measured. Then repeat the process of watching for 0 ammonia, 0 nitrites and 20 ppm nitrates. This will be the best process for any future additions you make to this and any other tanks you may own. You never want to add a lot of fish at one time as their waste will overwhelm you bacteria colony. The key will be patience. By slowing adding the fish you want to your tank you will ensure their health.

 

[fisherman26]

I think im finally seeing a little ammonia not quite to the .25 level and i have
5ppm nitrate but i havent seen any nitrite yet, wouldnt i see nitrite before nitrate? Im just keeping the danios until its done cycling then ill take them back to the pet shop and get a few fish then take it slow on adding fish.
Thanks for all the help oneal1969 Its just kinda frustrating not knowing alot about this stuff but im trying to keep everything safe for the fish.