Chloramine-T (Halamid) for Aquaculture
A broad-spectrum aquaculture disinfectant that can be used with fish and shrimp present. Chloramine-T disinfects tanks, nets, equipment, vehicles and well boats, and treats water against bacterial gill disease, external columnaris and common parasites in fish farms and hatcheries.
Chloramine-T in aquaculture at a glance
Chloramine-T (sodium p-toluenesulfonchloramide trihydrate), sold as Halamid, is a powdered disinfectant dissolved in water before use. Its wide safety margin between the dose that kills pathogens and the dose that harms fish makes it one of the few disinfectants that can treat water while fish or shrimp are in it.
- Surfaces and equipment: 0.5 to 2% solution (5 to 20 g per litre), 30 minutes contact.
- Footbaths: 2% solution, refreshed as often as needed.
- Bacterial gill disease in salmonids: 12 to 20 mg/L for 60 minutes a day, 3 treatments.
- Raceway water treatment: 10 to 20 mg/L for 1 hour, then flush.
- Stagnant ponds: 3 mg/L once a week.
Why fish farms use Chloramine-T
Aquaculture depends on strict hygiene to prevent disease, fish welfare problems and heavy financial losses. Chloramine-T has been used for many years as a universal farm disinfectant, from nursery and grow-out tanks through to the fish processing plant. It destroys pathogenic bacteria, viruses and parasites quickly, and it is effective against the bacteria behind bacterial gill disease and external columnaris, as well as parasites such as Gyrodactylus and the amoeba that causes amoebic gill disease.
Where it is used on the farm
Hatchery
- Broodstock tanks
- Tank water pre-conditioning
- Fish eggs
- Equipment and Artemia
- Waste water
Nursery
- Nursery tanks
- Water pre-conditioning and quality maintenance
- Fry and post-larvae
- Equipment and Artemia
Grow-out
- Tanks, basins and pond bottoms
- Pond water conditioning
- Nets and equipment
- Waste water
Processing plant
- Machinery and equipment
- Transport vehicles
- Well boats
- Waste water
Chloramine-T dosing chart for aquaculture disinfection
Always clean before you disinfect. Dirt and organic matter shield microorganisms from the disinfectant, so dry clean first, then wash with water or a detergent, then apply Chloramine-T dissolved in clean water.
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| Application | Concentration | Contact time | How to apply |
|---|---|---|---|
| Tanks and ponds (empty) | 1% (2% for resistant organisms) | Spray or rinse | Clean between production cycles, then spray or rinse all surfaces. |
| Equipment | 0.5 to 1% (2% for resistant organisms) | 30 minutes | Spray, or dip in the solution. |
| Nets | 1 to 2% | 30 minutes | Clean and disinfect between production cycles. Tested safe on polyamide 6 nets. |
| Vehicles | 1% | Spray | Disinfect the whole vehicle, not only the wheels, before it enters the farm. |
| Well boats | 1 to 2% | Between every transport | Rinse with water afterwards if needed to remove residue. |
| Footbaths | 2% | Refresh as needed | At every building entrance. Soak visitor footwear in 1%, renewed weekly. |
| Fish eggs | 1 g/L | 10 to 15 minutes | Dip, then wash with clean water. |
| Artemia nauplii | 60 mg/L | 3 minutes | Then rinse with clean water (FAO recommendation). |
| Raceways (water treatment) | 10 to 20 mg/L | 1 hour | Flush with fresh water. Repeat up to 4 times on consecutive or alternate days. |
| Stagnant ponds | 3 mg/L | Ongoing | Once a week. |
Conversions: 1% = 10 g per litre. 1 mg/L = 1 ppm = 1 g per cubic metre (1,000 L).
Adjust for your water: use a lower concentration in acidic water and a higher one as water hardness increases. Chloramine-T can inhibit nitrification, so take a biofilter offline before treating a recirculating system, or contact us first.
Fish disease treatment with Chloramine-T
Chloramine-T is used as a 1 hour static bath or flow-through treatment to control mortality from external bacterial infections, and as a freshwater bath additive against amoebic gill disease.
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| Disease | Fish | Dose | Treatment |
|---|---|---|---|
| Bacterial gill disease (Flavobacterium spp.) | Freshwater-reared salmonids | 12 to 20 mg/L | 60 minutes a day on 3 consecutive or alternate days |
| External columnaris (F. columnare) | Walleye | 10 to 20 mg/L | 60 minutes a day on 3 consecutive or alternate days |
| External columnaris | Warm water finfish | 20 mg/L | 60 minutes a day on 3 consecutive or alternate days |
| External flavobacteriosis | Cultured fish | 10, 15 or 20 mg/L | 1 hour bath, 1 to 3 times on consecutive or alternate days |
| Amoebic gill disease (Neoparamoeba) | Salmon | 10 to 25 mg/L | 1 hour freshwater bath; effective in seawater too |
Recognising bacterial gill disease
Fish with gill parasites, bacteria or blocked gills flare their gill covers and breathe faster than normal. Fish short of dissolved oxygen tend to gulp at the surface instead. If well-defined patches of the normally red gills are white or off-white and slimy, bacterial gill disease is the most likely cause. It usually follows cold snaps, temperature stress, crowding or poor hygiene, so correct those conditions as well as treating.
How to treat
- Static bath: shut off the water flow, dissolve the dose completely in a separate container of culture water and mix it into the unit.
- Use it fresh: use the treatment solution immediately; do not store it. End the treatment by flushing with fresh water and resume normal flow.
- Flow-through: pre-charge the unit with a static dose, then meter in more solution to hold the target concentration for the treatment period.
Chloramine-T dose calculator
Grams needed = litres of water × dose in mg/L ÷ 1,000. For flow-through treatment, the litres are the flow rate in litres per minute × treatment minutes, added to the static pre-charge.
Hatchery, egg and Artemia disinfection
Fish eggs
- Plaice, cod and halibut eggs: dip in 1 g/L for 15 minutes, then wash with clean water.
- Grouper, milkfish and sea bass eggs: dip in 50 mg/L for 15 minutes, then hatch in water containing 3 mg/L.
Artemia and shrimp larvae
- Artemia nauplii: 60 mg/L for 3 minutes, then rinse (FAO).
- Artemia cysts: 30 mg/L added when cysts go in to hatch removes most bacteria.
- Shrimp nauplii: only from stage N4; they tolerate 100 mg/L for 30 seconds.
- Post-larvae: 6 mg/L daily in hatchery tanks helps prevent filamentous bacteria.
Reference disinfection procedures
| Procedure | Method |
|---|---|
| Surfaces | Spray, flush or mop with 20 g/L. Wash with clean water after 30 minutes. |
| Tank water pre-conditioning | Add 15 g per cubic metre. Wait at least 24 hours before further treatment. |
| Light surface disinfection | Spray, flush or mop with 3 g/L. Rinse after 30 minutes if needed. |
| Wash | Wash for 15 minutes with 1 g/L, then rinse with clean water. |
| Short dip | Dip in 100 mg/L for 15 minutes, then rinse with clean water. |
| Waste water | Add 15 to 50 g per cubic metre depending on organic load. Discharge after 24 hours. |
| Raceway set-up | 10 g per cubic metre; flush with fresh water after 1 hour. |
| Stagnant ponds | 3 g per cubic metre once a week. |
| Water quality maintenance | Dose depends on your conditions. Contact us for advice. |
Applying Chloramine-T to surfaces
Getting the best result
- Apply to surfaces that are almost, but not completely, dry. Wet surfaces dilute the solution; bone-dry surfaces need more of it.
- Use at least 150 mL of solution per square metre on non-porous surfaces.
- Rinse, brush, mop or spray. Keep sprayer pressure below 10 bar for coarse droplets that are not inhaled.
- Let treated surfaces air dry.
Good to know
- It can be dissolved in a neutral detergent (pH 6 to 8), but cleaning first and disinfecting second works best.
- It does not foam on its own, but works in foaming equipment, which helps on vertical surfaces.
- Disinfection cannot be checked by eye, so follow a set routine.
- Stock solutions stay stable for months when kept in the dark.
What Chloramine-T kills
Chloramine-T is effective against Gram-positive and Gram-negative bacteria, fungi, and both naked and enveloped viruses. The World Organisation for Animal Health (OIE) recommends a 1% solution to disinfect equipment against Gyrodactylus salaris and recognises it as effective against IPN and ISA viruses.
Bacteria
- Aeromonas salmonicida (furunculosis)
- Flavobacterium branchiophilum (BGD)
- Flavobacterium columnare (columnaris)
- Flexibacter maritimus (marine columnaris)
- Vibrio anguillarum
- Vibrio harveyi
- Vibrio salmonicida
- Vibrio parahaemolyticus
- Yersinia ruckeri (redmouth)
- Escherichia coli
- Salmonella Typhimurium
- Bacillus subtilis spores
Parasites
- Gyrodactylus salaris
- Ichthyobodo necator (Costia)
- Ichthyophthirius multifiliis (white spot)
- Neoparamoeba (amoebic gill disease)
- Epistylis
Viruses
- Infectious pancreatic necrosis (IPN)
- Infectious salmon anaemia (ISA)
Fungi
- Saprolegnia
- Aspergillus fumigatus
- Trichophyton equinum
Safety and environment
Handling
- Mild product with no immediate harmful effect on skin, eyes or clothing, but do not inhale the powder or leave it on skin for hours.
- Wear a dust mask when preparing solutions.
- Wash skin contact with soap and water.
- Where it is used in water with live fish, check local aquaculture and veterinary regulations.
Environment
- Low acute toxicity (oral LD50 in rats and mice about 1,000 mg/kg).
- Readily biodegradable, not adsorbed by soil or sludge, and does not bioaccumulate.
- Forms no chlorine or hypochlorous acid, so no chlorinated organic compounds (AOX).
- Fish treated with Chloramine-T showed no residues after two weeks in residue studies.
Toxicity to aquatic species (mg/L)
| Species | Test | Result |
|---|---|---|
| Rainbow trout (Salmo gairdneri) | 1 h / 8 h / 24 h NOEC; 96 h LC50 | 100 / 50 / 10; 2.8 |
| Channel catfish | 96 h LC50 | 3.8 |
| Fathead minnow | 35 day NOEC; 96 h LC50 | 1.5; 7.3 |
| Guppy | 96 h NOEC | 1.2 |
| Gold guppy | 48 h NOEC | 20 |
| Harlequin fish | 48 h LC50 | 1.8 |
| Roach | 48 h LC50 | 60 |
| Water flea (Daphnia magna) | 48 h NOEC; 21 day NOEC | 1.8; 1.1 |
| Gulf white shrimp (mysis) | 24 h LC50 | 20 |
| Blue shrimp post-larvae | 72 h NOEC | 10 |
| Giant tiger shrimp | 24 h LC50 | 100 |
| Artemia nauplii | 72 h NOEC; 72 h EC50 | 10; 25 |
NOEC: highest concentration with no observed effect. LC50: concentration lethal to 50% of test animals.
Frequently asked questions
Can Chloramine-T be used with fish in the water?
Yes. Chloramine-T has a wide safety margin between the concentration that kills microorganisms and the concentration that harms fish, so it can be used as a water treatment with fish or shrimp present, typically at 10 to 20 mg/L for 1 hour followed by flushing with fresh water.
What is the dose of Chloramine-T for bacterial gill disease?
For freshwater-reared salmonids, use 12 to 20 mg/L as a static bath or in flowing water for 60 minutes a day, on 3 consecutive or alternate days.
How much Chloramine-T do I need for 1,000 litres?
1 mg/L equals 1 gram per 1,000 litres. So a 10 mg/L treatment needs 10 g per 1,000 litres, and a 20 mg/L treatment needs 20 g.
Is Chloramine-T the same as Halamid?
Yes. Halamid is the trade name for Chloramine-T (sodium p-toluenesulfonchloramide trihydrate), the active ingredient.
Will Chloramine-T harm my biofilter?
It can inhibit nitrification, so take the biofilter offline before treating a recirculating system, or contact us for advice on your setup.
Does Chloramine-T produce chlorine?
No. It acts without forming chlorine or hypochlorous acid, so it does not create chlorinated organic by-products (AOX). It is readily biodegradable and does not bioaccumulate.
Can I use Chloramine-T in a koi pond?
Yes, it is widely used by koi keepers against external bacteria and parasites such as flukes. Water hardness and pH affect the right dose, so see our koi treatment guide before dosing.
Related products and guides
Order Chloramine-T from Ecotao
Buy online on the Ecotao Store, or contact us for bulk quantities and dosing advice for your system. Call +27 21 911 5835 or email sales@ecotao.co.za.