Bacteria

[Caliban07]

Here's a question that's been playing on my mind for a while.

In a new tank, a colony if heterotrophic bacteria begins to grow that feast on organic compounds releasing ammonia for the autotrophs.

When we do a fishless cycle using pure ammonia. Are we bypassing the heterotrophs completely? What are they consuming if we are not adding anything such as fish waste or flakes. What if we have fake plants also?

Does tap water contain enough to keep them going or do they lay dormant until fish are added? Would it be better to add flakes as well as ammonia?

I understand that the heterotrophs reproduce very quickly but I was just wondering if it was possible to starve them at this stage.

This could be a completely dumb question but what are your thoughts?

 

[Fresh2o]

Good question. If using pure ammonia, then yes, the heterotrophs are being "ignored". If using fish food flakes or raw dead shrimp, then I believe the heterotrophs will play a role in breaking down the proteins into amino acids and eventually ammonia.

 

[Caliban07]

Yeh. So I was just wondering what happens to them? Do they die off and come back when organic materials are present?

Or could they, in order to survive, turn to inorganic compounds?

 

[jlk]

Yeh. So I was just wondering what happens to them? Do they die off and come back when organic materials are present?

Or could they, in order to survive, turn to inorganic compounds?

Unless your using solely RO water, your tap contains sufficient dissolved organics to feed heterotrophic bacteria. Heterotrophic bacteria exist in abundance everywhere and multiply very rapidly. These are also the bacteria behind bacterial blooms in tanks (particularly new tanks). You actually do not want these guys to grow and multiply out of control as they can outcompete your autotrophic nitrifying bacteria for oxygen.

Your not skipping a step or starving anything fishless cycling with ammonia. Also keep in mind that the largest source of ammonia in our tanks comes directly from the fish's gills, not from waste or debris that is decaying as the result of heterotrophic bacteria.

 

[Caliban07]

Yeh I mean I understand what you are saying about the fish producing more Ammonia. I was just referring to a fish less cycle and the fact that fish Arn't present. I just wasn't sure if there was enough organics in the tap water to sustain the heterotrophs. A reason why water changes are a good idea during a cycle perhaps? I've read lots of opinions that you shouldn't water change during a cycle.

 

[jlk]

Sometimes wcs are necessary in a fishless cycle. I would not be too concerned with heterotrophic bacteria and assuring they have an adequate supply of food. They are present and double at a rate of every 20 minutes (I believe) versus autotrophic bacteria that take over 20 hours to multiply. Most of us have no desire to see or deal with bacterial blooms from heterotrophs (due to excess organics) and they are counterproductive to establishing nitrifying bacteria.

 

[Caliban07]

But an important part if the cycle non the less. I can see now though that fish less cycle using pure ammonia is giving the autotrophs a head start if you like.

 

[Fresh2o]

But an important part if the cycle non the less. I can see now though that fish less cycle using pure ammonia is giving the autotrophs a head start if you like.

Yes (head start for autotrophs).
In some situations such as aquaculture and SW, heterotrophs are discouraged by removing the waste from the water before it has a chance to start breaking down. Cone shaped tank bottoms, settling chambers and filter socks emptied daily allow the solid waste to be removed intact as opposed to being churned into oblivion by pumps/impellers in a "normal" aquarium setup. Less waste, better water quality.