I bought a used 55 gallon with filter etc. a couple of weeks ago. I was planning on doing a fish in cycle and started with half a dozen danios plus some tetras that i had in fish bowls (that really didnt belong in fish bowls but i was a complete newbie when i bought them and didnt realize this, thus why i moved them to the 55 gal before it cycled, thought they had a better chance of surviving). I've been testing the ammonia and nitrites everyday since i put the fish in (about a week and a half ago) and have yet to test above zero on either. I've read in some posts that if the filter media and gravel is used it will produce an almost "instant" cycle if you start with only a few fish. The filter on my tank has both the biowheel and a cartridge filter. When i set up the tank i used the gravel that had been previously used and had to put a new cartridge filter in. I was told that for the past few months this tank had been set up with water still in it but no fish, even though fish had been kept in it previously. I was wondering if there was anyway that the gravel and biowheel could have possibly still had bacteria on them and thus caused an "instant" cycle and thus be the reason why the ammonia and nitrites are still at zero.
question...
- Thread starter tessalion
- Start date
I think you are referring to gravel used by the previous owner in the tank? probably was dry? If so, I don't believe so. If you mean that you bought the tank, they took it down, you took it to your house and put it up within hours of its having fish in it, and filled it and put fish in it immediately, then yeah, i suppose so. In order for used gravel to have live bacteria on it, it needs to have stayed wet and the bacteria need to have had a food source up until a short time ago, maybe a day, I think. One of the more experienced fishkeepers here will correct me if that's wrong. 
Well its possible that the tank still had bacteria in it...but the way you'd be able to tell is if your nitrates are going up at all. If you have 0 ammonia and 0 nitrites but your nitrates are going up then your tank is cycled. (note that SOME tap water has nitrates in it...so if you find nitrates be sure to test your tap water for them before ecstatically thinking your tank has cycled )
If you also dont have any nitrates then its more likely that you just dont have a very big bioload for the tank (a few danios and tetras in a 55 isn't exactly going to overload the system) so your ammonia isn't going to start to build up yet.
)If you also dont have any nitrates then its more likely that you just dont have a very big bioload for the tank (a few danios and tetras in a 55 isn't exactly going to overload the system) so your ammonia isn't going to start to build up yet.
