Bacterial Blooms Explained

[Prime Ordeal]

I just wanted to make sure I'm understanding this correctly. From my reading of this article and the Nitrogen Cycle I'd like to confirm the following:

1) The Nitrospira are the autotrophs
Nitrospira are one type of autotroph
2) The Nitrosomonas are the heterotrophs
No, nitrosomonas are autotrophs too (and FYI nitrosospira, another ammonia eating autotroph, are more likely to be in your tank than nitrosomonas).
3) The Nitrosomonas are the ones that are permeating throughout the water and causing the cloudy water as they reproduce too fast to attach to anything
No, that's the job of the heterotrophs (bacteria that feed on organics).
4) 99% of the Nitrospiras are located in the filter because they reproduce slower and attach themselves to the filter
Most of the nitrifying bacteria, i.e. nitrospira, nitrosospira and nitrosomonas are resident in what's called a slime matrix or EPS in the filter. They are sessile bacteria, i.e. they need a hard surface on which to live (effectively).
5) The oxygen levels should be quite low because I have a bunch of heterotrophs consuming it and converting it to ammonia, thus...
The article is partly wrong here. The heterotrophs can both produce ammonia by consuming organics or they can consume ammonia. Which they do depends on the carbon to nitrogen ratio at any particular time. But whatever they do they always consume oxygen and, while a bacterial bloom is not usually a problem, if it happens in a fish-in cycle and there is already low oxygen levels then it can be fatal. Also it robs the nitrifying bacteria of oxygen.
6) The ammonia levels should be high because of ^^
Normally ammonia will be produced so it may rise.
7) These increased levels of ammonia allow more autotrophs, aka Nitrospira, to grow and generate a colony on the filter
In general more ammonia will encourage the growth of more nitrifying bacteria which are all autotrophs.

Is this all correct? I've just started my first tank with my girlfriend (no fish or plants yet) and this site has been making it all incredibly clearer, so thanks in advance.

 

[Wond3rBoi]

I just wanted to make sure I'm understanding this correctly. From my reading of this article and the Nitrogen Cycle I'd like to confirm the following:

1) The Nitrospira are the autotrophs
Nitrospira are one type of autotroph
2) The Nitrosomonas are the heterotrophs
No, nitrosomonas are autotrophs too (and FYI nitrosospira, another ammonia eating autotroph, are more likely to be in your tank than nitrosomonas).
3) The Nitrosomonas are the ones that are permeating throughout the water and causing the cloudy water as they reproduce too fast to attach to anything
No, that's the job of the heterotrophs (bacteria that feed on organics).
4) 99% of the Nitrospiras are located in the filter because they reproduce slower and attach themselves to the filter
Most of the nitrifying bacteria, i.e. nitrospira, nitrosospira and nitrosomonas are resident in what's called a slime matrix or EPS in the filter. They are sessile bacteria, i.e. they need a hard surface on which to live (effectively).
5) The oxygen levels should be quite low because I have a bunch of heterotrophs consuming it and converting it to ammonia, thus...
The article is partly wrong here. The heterotrophs can both produce ammonia by consuming organics or they can consume ammonia. Which they do depends on the carbon to nitrogen ratio at any particular time. But whatever they do they always consume oxygen and, while a bacterial bloom is not usually a problem, if it happens in a fish-in cycle and there is already low oxygen levels then it can be fatal. Also it robs the nitrifying bacteria of oxygen.
6) The ammonia levels should be high because of ^^
Normally ammonia will be produced so it may rise.
7) These increased levels of ammonia allow more autotrophs, aka Nitrospira, to grow and generate a colony on the filter
In general more ammonia will encourage the growth of more nitrifying bacteria which are all autotrophs.

Is this all correct? I've just started my first tank with my girlfriend (no fish or plants yet) and this site has been making it all incredibly clearer, so thanks in advance.

Thanks a bunch for the clarifications. Would you mind telling me the name of the hetereotrophic bacteria? Also am I correct in saying that these heterotophs are what's causing the cloud to appear?

 

[Prime Ordeal]

Thanks a bunch for the clarifications. Would you mind telling me the name of the hetereotrophic bacteria? Also am I correct in saying that these heterotophs are what's causing the cloud to appear?

Predominantly the heterotrophs are Bacillus and Pseudomonas and yes it's these heterotrophic bacteria which cause the bacterial bloom and never the slow-growing nitrtifiers (the autotrophs).

 

[Man of fish]

Congratz on getting it pinned and now your also a mod
It helped me out a lot with my bacterial bloom and now I understand better

 

[OldMan47]

Not at all a MOD. PO is a member that has found lots of answers on the web, or maybe from other sources. MODs do work that most members never get to see. We basically try to keep things on an even keel. If we happen to have expertise in a given area, that is a bonus, not essential to being a MOD.

 

[Man of fish]

I was talking about backtotropical. The one who originally wrote it....

 

[deanwilkinson1989]

hi guys,

basically like the previous poster I have started a new tank with my fiancee and believe I have this problem. The tank has been cycling for about 10 days now (with no fish in it)

Day 1 - All equipment was cleaned and added to tank, tap water was added and left until day 3 to allow chlorine to evaporate off.

Day 3/4 - Tested Chlorine levels, indicate zero and pH of 7.5 which is apparently ideal. Bought a new water starter kit which contained something to reduce hardness and remove heavy metals and was added on this day.

Day 5 - First load of "Filter Start" was added. It was within a couple of hours that I noticed the water became cloudy. It has now been cloudy since then but tests of Ammonia and Nitrite levels suggest zero ppm of both (pH is also ok). I am of the opinion that I should wait for the water to clear up a bit before adding fish, however my partner is a bit impatient and wanting to add fish now. Would it be dangerous to the fish to add them during this bloom and what are the like consequences (to the fish and water chemistry) of doing so?

Cheers for your help in advance,

Dean

 

[Mr Tomato]

Bacterial Blooms - Explained

Every fishkeeper has experienced a bacterial bloom at some point. They are common in new set-ups which are cycling, but can happen at any time. The water goes cloudy, almost like someone has poured a drop of milk into the tank, and no matter how many water changes you do, it doesn't go away. Sound familiar?

I hope to explain here exactly what a bacterial bloom is, the effect it can have, how to treat it and how to prevent it.


The Nitrogen Cycle

To fully understand about bacterial blooms, a knowledge of the Nitrogen Cycle is required. If you are unsure of the Nitrogen Cycle or don't know what it is, it may be helpful to read the linked topic below first. This is particularly relevant if you have recently set up the tank, as the cloudiness is most likely an indication of other problems.

The Nitrogen Cycle


What is a Bacterial Bloom?

There are 2 types of bacteria at work in our tanks

Autotrophic Bacteria - Bacteria capable of synthesizing its own food from inorganic substances, using light or chemical energy. Our beneficial filter bacteria are autotrophs.

Heterotrophic Bacteria - Bacteria that cannot synthesize its own food and is dependent on complex organic substances for nutrition. The heterotrophs in our aquariums mineralise the organic waste (break down the uneaten food, fish waste, dead plant matter etc into ammonia).

Contrary to popular belief, it is commonly the heterotrophs which are seen in our bacterial blooms, not our trusted autotroph nitrifiers.

It is the heterotrophs which are primarily responsible for creating the "bio-film" (slimy residue found on the tank walls and ornaments) which builds up in our aquariums.

The heterotrophs are generally bigger than the autotrophs and therefore don't attach themselves to surfaces with the same ease. They also reproduce much more quickly. Heterotrophs can reproduce in around 15 - 20 minutes, whereas autotrophs can take up to 24 hours to reproduce.

In a newly set-up aquarium, the heterotrophs get to work quicker than the autotrophs, causing the 'cycling bloom' we so often see. Blooms are almost certainly heterotrophic if they are caused by a build up of organic waste in the substrate, which most, if not all, are.

Bacterial blooms are common in tanks with apparently no organics present (for example, where all that is in the tank is water and ammonia for a fishless cycle). This is caused by the dechlorination of the water suddenly enabling the water to support bacterial populations. The heterotrophs immediately get to work on the organics in the water itself. The severity of the bloom and even whether a bloom happens at all is dependant upon the level of organics contained in the water supply.

Our autotroph nitrifiers are strictly aerobic (require oxygen), but the heterotrophs can be facultative anaerobic (they can switch between aerobic and anaerobic function depending on their environment). Therefore the heterotrophs in the substrate will be in their anaerobic state and breaking down the organic waste into ammonia, but if they bloom up into the water column, they will switch to their aerobic form and will start to convert the ammonia back to nitrite, although very inefficiently. The heterotrophs are around 1,000,000 times less efficient at ammonia oxidisation than our beneficial autotrophs as the heterotrophs are not true nitrifiers.


The Effects of a Bacterial Bloom

Most of the bacteria in the aquarium are aerobic as it is a oxygen dominated environment, and these bacteria require lots of oxygen. When the heterotrophic bacteria bloom into the water column and switch to their aerobic state, this is a big drain on the oxygen content of the water. Oxygen depravation is the only risk to the fish which i am aware of during a bacterial bloom, as the heterotrophs themselves are harmless to fish, so good advice is to increase aeration!

To help you to understand why bacterial blooms occur, overfeeding ,dead fish or dead plant matter will cause a rise in the reproduction of the heterotrophs in order to break down the organic waste, they re-produce too quickly to be able to attach themselves to a surface and this causes a bacterial bloom. As the ammonia production increases due to the increased mineralisation, the nitrifiers are slow to catch up (as i said above) and so you see an ammonia spike until the autotrophs reproduce enough to take care of it. Contrary to popular belief, bacterial blooms cause an ammonia spike, not the other way around.

It is unclear whether the autotrophic nitrifiers ever bloom into the water column or if they simply multiply too slowly to cause this effect.


Treatment and Prevention of Bacterial Blooms

A thorough gravel vac will certainly help the situation, as will trying not to overfeed. Also, increase aeration as I noted above. Water changes will probably not clear the cloudiness as when you remove the free-floating heterotrophic bacteria, the others will reproduce more to compensate. Given the reproduction rate of the heterotrophs, it would require a 50% water change every 15 - 20 minutes just to stop the bloom getting worse, and even more if you want to make any progress towards clearing the bloom.

However, water changes won't exacerbate the situation as it will be heterotrophs (which are producing ammonia) which are removed from the water column via the water change. A water change will remove virtually no nitrifying autotrophic bacteria from the tank at all as 99% of the nitrifiers are housed in the filter, not in the water column. Water changes are not essential in clearing bacterial blooms, as left alone, they will usually dissipate within a matter of days.

Reducing the amount of organic waste in your tank is the ultimate solution to treating a bacterial bloom, and avoiding a build up of organic waste in the tank is the best way to prevent a bloom. The best way to do this is to maintain a regular aquarium husbandry routine involving water changes and substrate vaccuuming.

As I said above, blooms are common in tanks with apparently no organic waste present, most commonly when only water and ammonia are in the tank for a fishless cycle. In this case, there are few easy ways to remove the organics from the water, and so my best suggestion is to sit it out and wait. Water changes with purified water would help as it would dilute the concentration of organics in the water. Reverse Osmosis water would be ideal in this situation, however i would suggest that patience is the cheaper and more environmentally friendly option.

A bloom in an established tank indicates that there is a problem which has allowed a build-up of organic waste, usually in the substrate. This can be caused by excess dead plant matter, over-feeding which leaves food lying around the tank, or leaving dead fish in the tank. None of these are desirable in an aquarium and a bloom in your established tank will certainly indicate one or more of these causes present in the tank. If you experience a bloom in an established tank, improve your husbandry.

Please note: Unless otherwise stated, all text and images in this post are copyright Backtotropical, 2008-2011.

very interesting article,however..some more detailed advice would be useful on accurate water changing-and if to re-introduce tank safe again on those water changes during the bloom.

 

[Mr Tomato]

Some more info..fine tuned would be great. eg.. blooming, with new gravel and complete new set-up-'when bloom is on', adding new water-should one continue to add 'Filter start' as directed on the box? every 2 days until completion of suggested dosage or leave out the extra-until the bloom has settled? This is not written down on instruction leaflet. ta.

 

[monge_4]

Hi, I have a 55 gallon I just set up and am in the process of cycling it. I made the mistake of not using some of the water from my other tank, and used all treated tap water! So my question is if I put some rock, decor, and some water from my 29 gallon in to the 55 gallon will the built up bacteria on the rock, decor and water help reduce or speed up the process of getting rid of the cloudiness? Also would it help to put the used 29 gallon filter behind the 55 gallon filter to help build of the good colony of bacteria? Thanks Tyler... Back to rookie status for me...

 

[Man of fish]

Are you doing a fishless or fish in cycle? Yes the old 29 gallon filter is the best way to go, but the old water decorations etc won't do much. If there's fish in your 29 definately DO NOT put the filter pad in the 55 as then the fish in the 29 won't have a cycled filter and the cycle there will start all over again.

 

[kimmykat7]

O.k. Here's what I got from the article. Please tell me if I'm wrong. Since I have an already established tank with fish in it, I should clean the uneaten food & other debris more often, add a plant for a better cycle & breakdown of ammonia, only do periodic 25% water changes & maybe add some kind of good bacteria? P.S. My tank has all the symptoms of bacteria bloom. However, my test kit shows that the PH & ammonia levels are perfect.

 

[kimmykat7]

Also: I only have two neon tetras in a 1 gal tank. No filter etc...They have been happy little fish in this environment for 3 years. I'm pretty sure I over cleaned the tank 2 days ago. That's why I think I may need to add some sort of GOOD bacteria?

 

[fluttermoth]

It' very difficult to know what to recommend for an unfiltered tank. I'm very, very surprised your neons have lasted that long in such a tank, with no filter or plants.

What I can say (and I'm sorry if this sounds harsh) is that you're not really providing a good home for those fish. Quite apart from the fact that neons are shoaling fish that should be kept in groups of at least six (which you obviously don't have room for in a 1 gallon tank), you won't be able to keep the water stable with no filter.

You may have certain level of bacteria that have built up on the substrate and decorations, but the ammonia the fish are producing will build up in the water and then only be reduced when you water change. There's really no point adding any good bacteria, as unless they're in a filter, with a constant flow of water over them, they won't be able to do the job of keeping ammonia and nitrite at zero well enough to support your fish.

How exactly do you clean your tank, and what are the results (the actual numbers) from your tests?

 

[kimmykat7]

Oh. . Well they have seemed happy & healthy for the last 3 years. I can't afford to get a filtration system right now, but I can afford a new mini motor for the bubbler. Will that help? There was a plant in there for a while but the algae eater ate it. I forgot to mention there is also a tiny Chinese algae eater in there too. He if fine. The ammonia level is at 0. The PH is at 7.0. I don't have a nitrite reader. Thank you for your response.