Chloramine-T – Is it Safe for Pond Fish? (Dosage & Uses)

Pond Informer is supported by its readers. We may earn commission at no extra cost to you if you buy through a link on this page. As an Amazon Associate we earn from qualifying purchases.

Chloramine-T – Is it Safe for Koi & Fish? (Treatment Dosage, Uses, & Advice)

Chloramine T for pond water treatmentChloramine-T is most commonly used to treat a broad spectrum of bacterial infections, but can also help to control fungal infections as well as parasites. In fact, many hospitals as well as water treatment facilities use it as a disinfectant solution. It’s highly water soluble, and works by breaking down into hypochlorous acid that in turn releases chlorine and oxygen, with the chloramine ions also going to work in the water. The chloramine itself is able to hinder bacterial growth by destroying the bacterial DNA structure via oxidation, which in turn thwarts any microbial reproduction and reformation.

The primary byproduct of chloramine, chlorine (and, in fact, chloramine as well) is very reactive and able to easily bind to and react with organic compounds. This means that they’re both quite effective in treating things like algae overgrowth, bacterial gill disease, white spot disease, and a host of other issues, but of course are also toxic to aquatic life, particularly if used incorrectly.

What Does Chloramine-T Treat?

Chloramine-t treats fungi and parasites on fish
Chloramine-t is an effective treatment against a range of illnesses; including fungi, bacteria and parasites. Public domain.

As mentioned above, chloramine-t is a fungicide, algaecide, antibacterial/germicide, and virucide, so it helps to both treat and prevent a host of issues both inside and outside of ponds. In aquariums, aquaculture, and ponds, chloramine-t is most often used to treat bacterial gill disease but is also utilized to treat gill and skin flukes, fungal infections, costia, chilodonella, trichodina, and is particularly effective against myxobacteria.

Myxobacteria exist in soil but are also commonly found in pond sediments, where they’re known for lysing (or essentially breaking down) various algae species and cyanobacteria. While this is generally beneficial, myxobacteria can colonize inside of fish wounds and cause infections and illness. Because chloramine-t is so reactive and readily able to bind to organic compounds, it’s very effective at treating most of the above conditions either as a pond-wide treatment or a low-dose bath.

Is Chloramine-T Safe For Fish & Ponds?

Chloramine-T for use in koi ponds
Chloramine-T is very reactive in low pH, soft waters, so it’s better suited in ponds with higher pH and harder water. Public domain.

Chloramine-t is extremely reactive, and so should only be used in small doses and as a last resort rather than a first response since even low doses can cause issues such as gill burns and stress. Try utilizing more natural methods such as salt baths before resorting to chloramine-t treatments. Also don’t use chloramine-t while using any other medications or treatments (with the exception of salt), as chloramine-t can and likely will react with them and the results could be quite toxic to your fish.

It’s incredibly important to note that chloramine-t should only be used under very particular water conditions, and that it can itself impact water quality. In particular, pH and water hardness are the largest impactors of the chemical’s effectiveness – chloramine-t is much more toxic in soft, acidic waters (low alkalinity) (1) and so should be used in waters preferably with a pH of 6.5 or greater and moderately hard or hard water greater than 7°dH (130 ppm), assuming the “hardness” comes primarily from calcium, as calcium carbonate [CaCO3] . If you have soft water, a lower dose will be needed as the chloramine-t will be more reactive.

It’s also not effective if water temperatures are below approximately 11° C (approximately 52° F). Some fish are more sensitive to the treatment than others, and so chloramine-t should be used with great care with tench, orfe, or sturgeon. While chloramine-t can be used pond-wide, to prevent adverse impacts to non-impacted fish, vegetation, and any other wildlife present, it’s best to quarantine fish and only treat the quarantine stock tank(s). The treatment is  suitable for both  koi carp and goldfish.

Chloramine-T Dosage & Storage Information

Your dosage depends on your pond or tank size, the water quality parameters, and the fish species that are present as some may be more sensitive than others (rainbow trout, for example, are more tolerant to chloramine-t than, say, goldfish or koi (2)).

The table below provides approximate dosages for a range of water PH readings for both softer and harder waters. Firstly, check your pH parameter (most important) and then dose treatment based on hardness of water. Treatment within a separate stock or quarantine tank is always far more safe and effective than treating the entire pond system.

pH Softer Water (0-150 mg/L CaCO3)

Dosage Mg/Liter & Mg/Gallon

Harder Water (150+ mg/L CaCO3)

Dosage Mg/Liter & Mg/Gallon





5 Mg/L or 19 Mg/G

10 Mg/L or 38 Mg/G

15 Mg/L or 57 Mg/G

20 Mg/L or 76 Mg/G

10 Mg/L or 38 Mg/G

15 Mg/L or 57 Mg/G

18 Mg/L or 68 Mg/G

20 Mg/L or 76 Mg/G

In low pH waters (6.5 at the lowest) with soft water (low CaCO3 mg/L), you can dose at about 5.0 mg per liter, while higher pH (8 or above) hard water (high CaCO3 mg/L) will need a greater dose of around 20 mg per liter. Of course, this does depend on other water quality parameters as well as water temperature. For a more general dosage guide, you can utilize this calculator while keeping in mind the water parameters from the table.

Make sure that you’re continually aerating the pond or tank (separate stock tank is better), as chloramine-t will deplete oxygen levels over time. About 4 hours after treatment, change 25 to 50% of your water and treat it with a dechlorinator, since chlorine is one of the by-products of chloramine-t and can harm your fish. If needed, you can add more chloramine-t after 2 days, but no sooner than 24 hours after the first treatment.

When not in use, chloramine-t should be stored in a dark, ventilated area away from any other chemicals or, obviously, food. The storage area temperature should be at room temperature or below, 70° F (21° C) or under.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.