Available from December 2026

DNA BIOTEST Freshwater

All values in the green zone. And yet it isn't working.

Chemical water analyses describe what is dissolved in the water. They do not describe who converts it.

In every freshwater system, a bacterial apparatus is at work: nitrification, denitrification, breakdown of organic load, stability after every intervention. By far the largest share of these bacteria does not live in the free water but in the biofilm – on substrate, in filter media, on every wetted surface. Until now, this level simply could not be measured.

With the DNA BIOTEST Freshwater, it can. Total bacterial count, complete bacterial profile from water and biofilm, diversity indices and an interpretation that leads to concrete measures.

Combined with your ICP analysis, you get what has been missing in fishkeeping until now: a complete picture of chemistry and biology – at the same point in time, for the same system.

DNA BIOTEST Freshwater – Microbiome Analysis for Freshwater Systems

Water parameters describe the chemistry. The DNA BIOTEST describes the biology. Molecular biological determination of the total bacterial count and of the bacterial community in water and biofilm – with diversity indices and a clear results report. For aquariums, koi ponds, swimming ponds and breeding facilities. Combined with ICP analysis, it provides the complete picture for the first time.

Your water parameters are fine. Your system isn't.

Anyone who seriously runs freshwater systems knows this situation: the chemical parameters are unremarkable, the ICP analysis shows nothing critical – and yet the system isn't working. Recurring problems with livestock, unstable nutrient turnover after every intervention, breeding successes that cannot be reproduced.

The reason lies in a level that has not been measured until now: the bacterial community.

Nitrification, denitrification, the breakdown of organic load, buffering after disturbances – all of this is microbial work. And by far the largest share of these bacteria is not in the free water but in the biofilm on substrate, filter media and all submerged surfaces. This is exactly where it is decided whether a system works stably or only appears to.

What the DNA BIOTEST Freshwater determines

Water sample. System water is passed through a special filter on which the bacteria accumulate. This yields the total bacterial count and the composition of the bacterial community in the free water.

Biofilm sample. Swab taken with a cotton swab from a submerged surface – the second, decisive data level.

Both samples are prepared and analyzed in a specialist laboratory using modern molecular biological methods.

Your results report

• Bacterial profile for water and biofilm separately
• Total bacterial count as a quantitative indicator of the bacterial load
• Diversity indices for assessing microbial diversity
• Graphical presentation of all distributions
• Interpretation and recommendations on dominances and gaps in the system

Reading chemistry and biology together

ICP analysis and microbiome analysis answer different questions. One tells you which substances are present and in what concentration. The other tells you which biological apparatus converts these substances – and whether it works.

We recommend sampling at the same time. Both data sets then refer to the same system state: a conspicuous nutrient trend with an intact bacterial community is a control problem; the same trend with a shifted microbiome is a biological problem. Each calls for a different measure.

Single measurement or monitoring

For acute, unexplained problems, a single measurement provides a reliable snapshot. In breeding and holding facilities, pond systems and import stocks, ongoing monitoring is the more useful application: only the trend shows how stable a system really is and how it responds to filter changes, changes in livestock, feeding changes or treatments.

Who it is for

Demanding freshwater aquariums and aquascapes, discus and ornamental fish breeding, koi and garden ponds, swimming ponds and natural pools, pond fish farming, import and wholesale businesses, public facilities.

Analysis in a specialist aquatic laboratory

The evaluation is not carried out in a general environmental laboratory but in a laboratory specializing in aquatic systems. This is no minor detail: interpreting a bacterial profile requires knowing what a reef aquarium, a koi pond or an aquaculture facility normally looks like microbiologically. The same genus can be unremarkable in one system and a warning sign in another. Reference values and classification are therefore based on aquatic systems, not on drinking water or sewage sludge data.

The method: 16S rRNA sequencing

The basis is sequencing of the 16S rRNA gene – the bacterial marker gene regarded as the standard in microbiome research. The bacterial DNA is isolated from the water and biofilm samples, the marker region is amplified by PCR and then sequenced. The sequences are assigned using curated reference databases.

The difference from conventional bacterial counts on culture media is fundamental: cultivation methods only capture what can be grown in the laboratory – depending on the system, a single-digit percentage of the bacteria actually present. Sequencing captures the community as it exists in the system.

Potentially pathogenic genera

The analysis is not limited to the “good” bacteria. The entire bacterial community is captured – including genera regarded as potentially pathogenic to fish and invertebrates, such as Vibrio, Aeromonas, Pseudomonas or Mycobacterium. You find out whether these groups are present in your system and what share of the community they make up.

What matters is not so much their presence as their share: many of these genera are part of the normal colonization of aquatic systems. It becomes critical when they dominate or increase significantly over time. This is exactly the shift the test makes visible – before it shows up in your livestock.