First, rbishop, I'm still waiting for those articles you promised that would sway my opinions on fish-in cycling :look: . Second, given that (from our friendly convo) you're very biased against fish-in cycling I'd like to point out a few things about your post. It's very good, but needs to be made a little bit more fair. You almost, sort of, kind of presented fish-in cycling as an option but still adopted your stance that most people are going to mess up and wind up killing their fish. It's not that you came out and said as much. Just more of an overall tone that was in the article. Please, try to give people more credit than that.
This is the first anomally that I want to point out. With both of these methods, you are a slave to testing water parameters. However, with fish-in cycling, you are only going to be doing it for about 1 week. Then, every time you add more fish, you'll be doing regular testing for another week. That's it. For fishless cycling, you're testing regularly for many, many more weeks. I'd also like to point out that, every time you add ammonia, you have to test. You'll probably have to test SEVERAL times until you get to the correct level. Why paint the testing in fish-in cycling as a negative when you're doing even more testing for longer in a fishless cycle? Also, you don't need to test twice daily. If you're starting with small numbers of fish, you shouldn't have to test that frequently. I started off testing twice daily and found that I was getting 0 ppm ammonia for at least 2 days straight. All I was doing was stressing MYSELF out while my fish looked at me through the glass and chuckled.
I think you left out some important details on how to do a proper and safe fish-in cycle. In doing so you are swaying the reader away from this very viable option. So, in an effort to make your otherwise good post a little more balanced, I'd like to add some fish-in cycling info based on my own experience cycling my tank:
Fish-in cycling can work just as well as fishless cycling while giving you fish in your tank right from the start. You also don't have to deal with dosing ammonia or doing a huge water change at the end. If you're starting a big tank, this can be a real pain in the arse, especially if you do your "final" change out and discover that you won't be able to get fish right away for another few days. Then what? Refill the tank, dose again and then repeat when you can get the fish? What if you have a 100+ gallon tank? You're talking about a HUGE amount of work for that one.
To have a successful fish-in cycle you need to start off with a small number of fish. How small depends on the size of the tank and on whether or not you can get a hold of some filter media/gravel from an established tank. Or, another option is to use biospira. I just wouldn't trust bio-spira in a fully stocked tank. It can be a bit finicky and, if it doesn't work, you'll be stuck working with a fully stocked tank...not good.
So, you can start with a few fish, test every day or every other day and do water changes as necessary. Like I said, when I was fish-in cycling my tank, I was getting so many 0ppm readings that I gave up on testing every day and tested every other day. I also wasn't going to take any chances so, whether I needed to or not, I did a small water change of about 25% every other day or every other 2 days. After you get through your first mini-cycle (usually only takes a week) you can then add a few more fish and repeat. If you're dilligent, you can start up your tank this way quite nicely and never even come close to risking losing or stressing a fish.
You can make the process even safer by adding plants. Plants don't just consume nitrates. They can also take in ammonia. You would do well to add some easy to grow plants in a fish-in cycling tank. It can really help to eliminate the stress factor. In fact most people on this site recommend that, if you're going to start a planted tank, you should load it with plants from the get-go.
So, to sum up, you can safely execute a fish-in cycle. It is not guaranteed to stress or kill your fish. The only factor that can lead to that happening is you, the aquarium owner. You get out of fish-in cycling what you put into it. It is a lot of work. However, I feel the reward of having fish right away is worth it.
So, the pros:
No ammonia dosing and the testing that goes with it.
No hunting for pure ammonia (some here have trouble finding it).
No huge water changes that need to be carefully timed with the arrival of your fish.
Fish in the tank right away. No staring at an empty tank.
Cycles begin quicker and end quicker than in fishless cycling.
You stop testing religiously when you're done stocking, usually around 3 weeks.
With fish-in cycling, you are pretty much guaranteed to get a cycle. Some here have waited weeks or months for a fishless cycle to begin with no results and no idea why it failed.
You get used to the routine of testing and doing water changes and general tank maintenance.
The cons:
You need to do work. Testing may have to be done daily, even if it is for a shorter net time than in fishless cycling.
Water changes will need to be done frequently but in smaller volumes than fishless cycling.
While you can start with fish, you will have start with small numbers and add more, slowly, over the course of a few weeks until you're fully stocked.
You do risk stressing your fish. I put it in here as a warning to start off SLOWLY. You really do need to start off with only a few fish. I started with 6 zebra danios and six cories in a 55g. That's a small number of small, not so messy fish. The smaller the tank, the fewer fish you should start with. If you follow the guidlelines above this con will not happen. Like I said, it all depends on how much you put into it.
I would just like to reiterate, the purpose of this post is not to bash fishless cycling. It's simply to point out that there are pros and cons to both methods. The pros of fish-in cycling were not really pointed out in the original post and I just felt that, in the interest of fairness, they should be presented for all to see. It's my opinion that both methods are equally viable and neither should be villified over the other.
