Will Beneficial Bacteria Die w/ No Source of Ammonia?

[TygGer]

For instance, If I a tank has completely cycled but no fish or ammonia has been added to the tank for a couple weeks (or longer), will the beneficial bacteria die? And if so, I assume one would need to start the cycle all over?

 

[duaumun]

Hmmm, is your tank planted? I left my planted alone for a week and then i just added fish. Yeah, they will eventually die though. Why do you ask, if i may prod?

 

[An t-iasg]

The tank was cycled ok, and now it's empty?? An empty tank (set up with water but no fish or added ammonia) can't cycle. There is no benefit to setting up a tank and running for a few weeks to cycle -- it can't happen without ammonia and bacteria. You could do a fishless cycle to get the bacteria going again. I have used Bio-Spira a few times very successfully, but I guess it's unavailable for awhile.

My mom wants me to bring my bettas to her house when we go on vacation, because she likes to take care of them, but this wouldn't be a good idea. If I take the bettas out of the tanks, and put them in bowls at my mom's house, then all the established bacteria will die in the tanks. (Besides, the bettas won't like the little bowls anyway!) Sometimes, if the betta is in a QT bowl for only a few days, I still "feed" the tank a small amount of fish food. The resulting ammonia from the "rotting" food will sustain the bacteria for a few days while the betta is gone.

To answer your question, yes, the bacteria will die without a food source. The food source can be the fish, or ammonia you add as part of a fishless cycle. If the bacteria dies, then you have to start the cycle over.

 

[Aquafriend]

I had heard that as long as you add some fish food every day, that the tank will stay cycle indefinately.

 

[An t-iasg]

I had heard that as long as you add some fish food every day, that the tank will stay cycle indefinately.

I don't know about indefinitely, but my betta tank (5.5 gallons, the betta is the only one in there) stayed cycled through feeding for 6 days one time when the betta was in the QT bowl. I sprinkled a bit of cheap flake food (not what the bettas eat) on the sponge filter. When I did an ammonia test before putting the betta back in, the test was 0. But another time, the betta was out of the tank for 10 days, and the ammonia rose to .25, even though I fed the tank like I did before.

A community tank is different -- ususally you only QT one or two fish, and not the whole tank, so there are still plenty of fish to keep the cycle going. But when the betta's the only one in there, you have to be a little cautious about taking him out for long periods of time, and the effect that will have on the biological filter.

 

[deli_conker]

I had heard that as long as you add some fish food every day, that the tank will stay cycle indefinately.

I don't know about indefinitely, but I kept a QT tank cycled for about 6 months (before I decided to turn it into a normal tank) by just dropping excess thawed blood worms into it once or twice a week. The down side is that you still have to do water changes to keep the nitrAtes down...

 

[TygGer]

I asked because my parents wanted goldfish. I gave them my old filter media from my community tank to help jump start the cycle, but it's been about 3 weeks and they have not added fish. I'll need to check the water parameters for them...

They wanted to do a fishless cycle, but they did not add ammonia or a shrimp to the tank. Will the old filter media be enough to start the cycle? Additional to what normally gets trapped in the filter media, I know there was algae, old fish food and dead leaves from my plants.

 

[Christmasfish]

after three weeks it was probably a wasted effort, the bacteria is surely starved dead now..

you could run the filter in your tank for a week and then put it theirs with some of your media again for a head start.
I usually start new tanks with 50% water out of one of my other tanks since I change my 50s between 10-20 nitrates and old filter media. Instant ph perfect meedia starteed tank...
but I don't have any really messy fish like golds or cichlids and my tanks average at 3 small fish per 10 gallons.