Fishless Cycling

[Tobigara]

ok...say you go thru the fishless cycling process perfectly. your ammonia and nitrite readings have been 0 for a week and it's time to add the fish you want.

here's my question. if you cannot add the the full stock of fish you had planned for some reason (lfs only had half of your list), what happens to the bacteria that isn't needed to support the smaller stock you now have? does this question make sense?
does the excess bacteria die? if it does, does that mean that once i get the rest of my stock list that i can't just put them all in because the current amount of bacteria is only enough for the current bio-load?

i'm not sure if my question has any sort of importance to established tanks but it was a thought that crossed my mind...so i figured i'd ask

 

[fry_lover]

you dont need to fully stock after a fishless cycle, filter bacteria does not suddenly die off if you only stock a certain amount of fish. As long as the filter has a regular supply of ammonia and oxygen.

Unless you stocking a malawi tank, its not great practice to fully stock from the get go anyway, take your time, relax and enjoy!!!

 

[rdd1952]

you dont need to fully stock after a fishless cycle, filter bacteria does not suddenly die off if you only stock a certain amount of fish. As long as the filter has a regular supply of ammonia and oxygen.

Unless you stocking a malawi tank, its not great practice to fully stock from the get go anyway, take your time, relax and enjoy!!!

Actually, after doing a full fishless cycle it is best to fully stock the tank. You will certainly have enough bacteria to handle the waste. And although the bacteria don't die off in a short time frame, over the course of a week all of the excess bacteria will indeed die off. If there are only 3 fish in a 30 gallon tank for instance, there won't be enough ammonia present to feed a bacteria colony large enough to support a full stock in a tank that size.

In a fishless cycling situation, your ammonia and nitrite won't be 0 for a full week. When the tank is cycled it will be able to process 4 or 5 ppm of ammonia back to 0 ammonia and nitrite in about 12 hours. If you leave the tank for 7 days with no ammonia, all or most of your bacteria would die off and you would be back to square one.

Anyway back to the question If you can't find all the fish you want, get as many as you can. Even if that means the tank is only half stocked (or less). The additional bacteria would indeed die off. When you find the rest of the fish, you would have to finish stocking using the same method as doing a fishless cycle which you are in essence doing. Just add a few at a time (you can usualy double your bio-load without any problems as the bacteria can usually double it's mass in about 24 hours) and test. You will probably see a small amount of ammonia and nitrite for a day or 2 but that should be in.

 

[fry_lover]

you dont need to fully stock after a fishless cycle, filter bacteria does not suddenly die off if you only stock a certain amount of fish. As long as the filter has a regular supply of ammonia and oxygen.

Unless you stocking a malawi tank, its not great practice to fully stock from the get go anyway, take your time, relax and enjoy!!!

Actually, after doing a full fishless cycle it is best to fully stock the tank. You will certainly have enough bacteria to handle the waste. And although the bacteria don't die off in a short time frame, over the course of a week all of the excess bacteria will indeed die off. If there are only 3 fish in a 30 gallon tank for instance, there won't be enough ammonia present to feed a bacteria colony large enough to support a full stock in a tank that size.

In a fishless cycling situation, your ammonia and nitrite won't be 0 for a full week. When the tank is cycled it will be able to process 4 or 5 ppm of ammonia back to 0 ammonia and nitrite in about 12 hours. If you leave the tank for 7 days with no ammonia, all or most of your bacteria would die off and you would be back to square one.

Anyway back to the question If you can't find all the fish you want, get as many as you can. Even if that means the tank is only half stocked (or less). The additional bacteria would indeed die off. When you find the rest of the fish, you would have to finish stocking using the same method as doing a fishless cycle which you are in essence doing. Just add a few at a time (you can usualy double your bio-load without any problems as the bacteria can usually double it's mass in about 24 hours) and test. You will probably see a small amount of ammonia and nitrite for a day or 2 but that should be in.

was just wondering, is their any evidence that a certain level of bacteria will "die off" if you dont fully stock a fish tank after a fishless cycle, as i find this hard to believe. Who's doing all this monitoring of the amount of bacteria in the filter?

 

[rdd1952]

I don't have the evidence in front of me to back it up although I'm fairly certain it can be found on the internet but I think it makes perfect sense. Any living organism is going to eventually die from lack of food. How quickly they die off, I don't know. For humans, it would be a matter of weeks or months I guess. I would think bacteria, beiing tiny organisms would go much quicker. But without enough food, they certain will have to reduce their masses.

I will say that I recently cycled a 5 gallon tank using the normal 4 ppm of ammonia. It was processing that back to 0 in about 12 hours. I ended up using that tank as a Q-tank for 7 new neon tetras. They were in the tank for 2 weeks before being moved to their new home in my 29 gallon. Since I wanted to get more and didn't know when I would be able to get them, I added 4 ppm of ammonia to the tank to keep the bacteria fed. It took 3 days for that 4 ppm to drop back to zero. That in itself tells me that most all of the bacteria that I had originally buuilt during th fishless cycle had died off or the ammonia would have processed just as quickly as it was before putting the 7 neons in. Obviously they weren't producing anywhere near 4 ppm of ammonia a day so that additional bacteria wasn't needed and died off.

 

[fry_lover]

ok thanks for the info, i wont argue with that, your own experience with it is more use to me than scanning Google right now.

However, when we fishless cycle we are flooding the bacteria with high levels of ammonia, perhaps that why SO much bacteria builds up, some of it maybe died when you put 7 Neons in there, simply because there was no longer a a massive amount of ammonia in the water.

I guess what i am saying is... yes i can see how some bacteria may die off, but perhaps its insignificant anyway....

It's like winning the lottery ($100 million say) and losing $90 million the next day (90%), doesnt really matter, you still going to be able to meet your needs and objectives with the remaining 10%

i might be digressing here Ruud, perhaps even contradicting myself... not sure!

I would say i could well believe some bacteria would die off then, especially going by your example with the neons

OR, what about this....

perhaps the bacteria did not die off, they just became "used to" dealing with a certain amount of ammonia when the neons went in and needed time to get used to more ammonia when you flooded them with ammonia again!!!

If your eating a simple salad everyday for dinner then someone suddenly puts x10 hamburgers and x10 pizza's infront of you for dinner, are you going to be able to able to eat all that? LOL

 

[rdd1952]

You are definitely right about building an enormous amount of bacteria. I definitely don't hae the testing ability to find out for sure but I feel very certain that at the height of the nitrite spike of a fishless cycle that there is at least 40 to 50 ppm of nitrite present. Obviously there is no way any number of fish could ever produce enough nitrite to require than much bacteria.

Your salad/hamburger analogy is basically what I'm saying though. If you stock the tank with say 10 danios because you can't find the 15 rainbows that you want to put in with them. There will be enough bacteria to process the waste of the 10 danios but when you add the 15 rainbows, the bacteria will hae to increase their masses to process the additional waste just as we would have to invite friends over to help eat the hamburgers and pizzas.

 

[Tobigara]

thank you rdd. i think i'm finally learning.