Promoting Fish Health- Five Steps to Exceptional Water Quality and Reduced Risk of Bacterial Infection

Promoting Fish Health-  Five Steps to Exceptional Water Quality and Reduced Risk of Bacterial Infection

Our hatchery-raised fish are free of bacterial infection and parasites. 

That is not true of fish that are sustainably harvested in the wild and transported to Tennessee.  We quarantine incoming arrivals and treat with Cu prior to moving into grow-out tanks.

If you have fish, you have organic waste (uneaten food plus organic material in the feces) and inorganic waste coming from urine including ammonia and other nitrogen-based products.

If you have fish in your tank,  you have bacteria.

But not all bacteria are the same. 

Organic Waste & Bacteria

There are lots of bacteria that will eat organic matter. 

These bacteria fall into class called heterotrophic anaerobic bacteria.

"Heterotrophic” means they can’t make their own sugar so have to eat it and "anaerobic" meaning they don’t need oxygen in order to live.

Let’s call this gang the “Heteros.”

Unfortunately fish are also organic matter.  There are several variants of Heteros that will infect your fish, especially any fish that are stressed or have lesions. 

Makes sense.  Same reason why humans should not swim in sewerage contaminated water.  There will be a Hetero present that can easily infect you. 

Ammonia & Bacteria

There are bacteria that will dine on the ammonia in urine.   These fall into a class called chemoautotrophic aerobic bacteria.  “Chemoautotrophic” means they use chemistry to make their own food and “aerobic” means they use and need oxygen to do so.

Let’s call this gang the “Chemos.”  

The good thing about Chemos they can’t dine on your fish.. just their urine.

Can the Heteros and the Chemos be on the same block? 


The Heteros will beat out the Chemos for territory.

if you let the Heteros run wild, your organic load will drop but you are running increased risk of bacterial infection as the Chemos multiply and ammonia levels will increase. 

To manage ammonia,  many aquarium owners either do frequent water changes.  
As bio-density increases in more crowded tanks,  

As the biodensity increases,  water changes become more difficult to do and keep up with.  Some aquarium owners opt to  pull the pH lever. 

If you lower pH to around 7.2, toxic ammonia changes to non-toxic ammonium. And guess what?  the Heteros love it.  They thrive with lower pH and the more Heteros the more risk of your fish getting infected. 

 The Chemos?  They do best at pH 8.0.

if you use pH to control ammonia,  constantly treat your tank with Cu and undertake large and frequent water changes

Be very careful.   If you inadvertently raise your pH during the change all that ammonium will start converting back to ammonia and damage or even kill your fish. 

Is there a better way? 

At Sustainable Aquatics we developed a robust solution that delivers exceptional water quality. 

Here is what we do:

Step 1:  Starve the Heteros

We use filters (plus negatively charged glass bead filters on larger systems) to remove solid organic waste matter then protein skimmers for the rest. 

This step starves the Heteros and gives the Chemos a chance.

Step 2:  Operate at pH 8.0

Love for your fish and love for your Chemos. 

Both are happier at pH 8.0.  and slowing down any Heteros that are still hanging around.

Step 3:   Then Stomp on their Heads

We use UV to fry any Heteros that are left.  Strong bulbs, change every 10 months.
Step 4:  Install a Chemo-friendly Bioreactor

Remember Chemos need oxygen to thrive.  Give it to them.  Use large/water air exchange on light bio media that lots of surface area and participates in vigorous air-water turbulence.

Step 5:   Raise your Alkalinity & Buffer

Your Chemos make their own energy from ammonia but need alkaline compounds to do so.  We run alkalinity over 300 ppm and buffer to keep it there.

Other Advice?

Be very careful when buying a fish from a retailer that uses pH to control ammonia.   If you do,  quarantine and treat your new purchase with Cu and then put your fish into a system that follows these five steps.  You and your fish will be glad you did.

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