Chapter 13 Wound Care and Healing in Koi
In understanding wound healing in fish we should appreciate that their environment is much different to land mammals and that any wounds can cause problems beyond bacterial issues that being the entry of water into the fish’s body.
The mucus coating, scales and skin are all part of the fishes mechanism for preventing water from entering its body where it would interfere with the body fluids including the blood stream,
Because of this, wound healing in fish begins with a massive migration of skin cells to the injury site. This can often be seen as a lightly shiny slightly opaque coating around the wound site usually protruding beyond the normal body contour. This is because large quantities of skin cells are deployed to literally block the hole where damage occurs.
Once the damaged area is repaired, from the point of view of water ingress, the normal repair process can continue replacing lost skin, scale and mucus layer.
Because of the above facts it is important to be able to differentiate between damaged and infected tissue, and clean healing tissue as any errors in this diagnosis can mean that the masses of cells which have literally invaded the area to prevent water ingress can be destroyed simply by cleaning the wound at this stage. The new skin tissue is extremely soft and initially will be disturbed by even the gentlest of cleaning. Due to this a spray on medicating/sealer is best used in the early stages of healing.
In my experience ulcer damage usually heals without scar tissue and all scales regrow; some are indistinguishable from the original scales but quite often there is a colour mismatch. Scar tissue is probably more likely if new cell growth is damaged especially by harsh chemicals such as hydrogen peroxide and potassium permanganate.
There is a time when use of the above chemicals provides some benefit. When ulcers are initially detected it is very important that the infected area be cleaned well and that any infected tissue is removed. This can only be done when the fish is sedated.
It is important to remove any damaged and infected scales/skin completely around the wound or ulcer until good clean tissue is reached. At this stage I usually clean the whole area with 3% hydrogen peroxide and after foaming I wipe the area dry and apply a wound dressing; my preferred wound dressing is WoundMed. I have achieved spectacular results with this product. The first of three antibiotic injections would then be given using the base of the dorsal fin at the rear end as an injection site.
A koi’s immune system is quite effective at 14C and the metabolism is more than acceptable for tissue regeneration and for combating bacterial infections at 18C. Initial higher temperatures than this can favour the growth of bacteria; higher temperatures can speed up tissue regrowth but these are best avoided until the infection is well under control.
To give a better overall plan for wound healing we must also consider the environment in which the koi is living.
Temperature has been mentioned already and other serious considerations include good parameters which allow the koi’s natural immune system to take on the job of fighting disease such as bacterial infections. In suboptimal conditions the immune system is also suboptimal.
We must all be aware that when a koi has a bacterial infection, especially one which is systemic (within the koi’s body and bloodstream) it excretes the bacteria into the pond water environment in its urine and excrement. One of the main reasons why husbandry is so important in our koi ponds is because our koi use the area in which they live, sleep and eat as a toilet also. Our filter systems are in fact sewerage systems!! We must all be aware that this toilet water is continually in contact with the koi’s skin; as koi are continually drinking water so it is also within the gut as well as being in contact with the very delicate gills.
It naturally follows that any sensible means which will reduce the bacterial levels within the water column will be beneficial to all the members of the pond community, sick and well alike. When bacterial infections do occur in pond systems it is wise to keep the handling and netting of our koi to a minimum as the first line of defence for the skin is the mucus coating which can lose integrity when nets are used.
Initial water treatments with ChloramineT can be followed up with acraflavine and salt; this will allow some gentle soothing effect on the skin and other tissues whilst keeping bacterial levels down. The salt assists with osmoregulation problems and aids the reduction of general stress.
Salt is a valuable addition to pond water when koi have open wounds: it should be added at the rate of 5 Kg/tonne to give a 0.5% concentration. This will reduce the ingress of water into the body of the koi while the wound seals.
All bactericidal treatment will affect the biological activity of the filter system to some degree; new or immature systems are especially prone to being adversely affected whereas established, and especially filters which have seen treatments previously, are usually less affected. Acraflavine may be used with salt and should reduce the bacteria levels in the water column without undue adverse effect on the filter activity.
It is uncommon for the ammonia removing bacteria to be affected by conventional treatments but relatively common for the nitrite bacteria to have a little set back. Due to this any treatment which allows salt to be used in conjunction with it is preferred as the salt helps to prevent the uptake of nitrite into the koi’s bloodstream.
Antibiotics and their use with damaged and bacterially infected koi.
From time to time, the health of damaged koi may deteriorate due to bacterial infections, and the use of an appropriate antibiotic may be necessary. The law controls the use of antibiotics and these medicines can only be supplied by a Veterinary Surgeon.
Like the majority of medicines, antibiotics can have side effects and it is extremely important that the correct dose rates be used. Under dosing can allow strains of bacteria to evolve with resistance to the particular antibiotic being used and overdosing or re-dosing before the antibiotic has left the body can cause serious damage to the major organs.
Some koi showing symptoms of „dropsy“, that is raised scales over the majority of the body, may have kidney problems and the use of antibiotics is not always advisable until the excess fluid is excreted.
Below is a list of antibiotics commonly used for koi carp together with the dose rates which apply to their use.
Baytril is usually the first choice of antibiotic because it has a wide spectrum of activity and is effective against aeromonas and pseudomonas bacteria. However many vets favour sensitivity testing so that an antibiotic can be selected that specifically targets the bacteria causing the infection.
The following charts give details of the size/weight of the koi together with the appropriate injection dose in ml.
Baytril 5%
Interval 72 hr Dose rate mg/Kg= 10 mg/Kg
Interval 48 hr Strength mg/ml = 50 mg/ml
Dose rate mg/Kg= 15 mg/Kg
Strength mg/ml = 50 mg/ml
Size (inches) Size(CM) Weight(Kg) 10mg/Kg 15mg/Kg
5.5 14 0.02 0.004 0.006
7 18 0.05 0.010 0.015
8.6 22 0.1 0.020 0.030
10 26 0.2 0.040 0.060
12 30 0.32 0.064 0.096
13.5 34 0.5 0.100 0.150
15 40 0.75 0.150 0.225
17.5 45 1.17 0.234 0.351
20 50 1.68 0.336 0.000
22 55 2.38 0.476 0.714
24 60 3.18 0.636 0.954
26 65 4.25 0.850 1.275
27 67.5 6.75 1.350 2.025
27+ weigh Koi weigh Koi Calculate
Baytril 2.5%
Interval 72hr Dose rate mg/Kg= 10 mg/Kg
Interval 48hr Strength mg/ml = 25 mg/ml
Dose rate mg/Kg= 15 mg/Kg
Strength mg/ml = 25 mg/ml
Size (inches) Size(CM) Weight (Kg) 10mg/Kg 15mg/Kg
5.5 14 0.02 0.008 0.012
7.0 18 0.05 0.020 0.030
8.6 22 0.1 0.040 0.060
10 26 0.2 0.080 0.120
12 30 0.32 0.128 0.192
13.5 34 0.5 0.200 0.300
15 40 0.75 0.300 0.450
17.5 45 1.17 0.468 0.702
20 50 1.68 0.672 0.000
22 55 2.38 0.952 1.428
24 60 3.18 1.272 1.908
26 65 4.25 1.700 2.550
27 67.5 6.75 2.700 4.050
27+ weigh Koi Calculate Calculate
Gentamycin 80mg/2ml
Interval 72hr Dose rate mg/Kg= 5 mg/Kg
Interval 48hr Strength mg/ml = 40 mg/ml
Size (inches) Size(CM) Weight (Kg) Dosage (ml)
5.5 14 0.02 0.003
7 18 0.05 0.006
8.6 22 0.1 0.013
10 26 0.2 0.025
12 30 0.32 0.040
13.5 34 0.5 0.063
15 40 0.75 0.094
17.5 45 1.17 0.146
20 50 1.68 0.210
22 55 2.38 0.298
24 60 3.18 0.398
26 65 4.25 0.531
27 67.5 6.75 0.844
27+ weigh Koi weigh Koi
Gentamycin 20mg/2ml
Interval 72hr Dose rate mg/Kg= 5 mg/Kg
Interval 48hr Strength mg/ml = 10 mg/ml
Size (inches) Size(CM) Weight (Kg) Dosage (ml)
5.5 14 0.02 0.010
7 18 0.05 0.025
8.6 22 0.1 0.050
10 26 0.2 0.100
12 30 0.32 0.160
13.5 34 0.5 0.250
15 40 0.75 0.375
17.5 45 1.17 0.585
20 50 1.68 0.840
22 55 2.38 1.190
24 60 3.18 1.590
26 65 4.25 2.125
27 67.5 6.75 3.375
27+ weigh Koi weigh Koi
Amikin 100mg/2ml
Interval 72hr
Dose rate mg/Kg= 6 mg/Kg
Strength mg/ml = 50 mg/ml
Size (inches) Size(CM) Weight (Kg)
5.5 14 0.02 0.002
7 18 0.05 0.006
8.6 22 0.1 0.012
10 26 0.2 0.024
12 30 0.32 0.038
13.5 34 0.5 0.060
15 40 0.75 0.090
17.5 45 1.17 0.140
20 50 1.68 0.202
22 55 2.38 0.286
24 60 3.18 0.382
26 65 4.25 0.510
27 67.5 6.75 0.810
27+ weigh Koi weigh Koi
Amikin 500mg/2ml
Interval 72hr Dose rate mg/Kg= 6 mg/Kg
Strength mg/ml = 250 mg/ml
Size (inches) Size(CM) Weight (Kg) Dosage (ml)
5.5 14 0.02 0.000
7 18 0.05 0.001
8.6 22 0.1 0.002
10 26 0.2 0.005
12 30 0.32 0.008
13.5 34 0.5 0.012
15 40 0.75 0.018
17.5 45 1.17 0.028
20 50 1.68 0.040
22 55 2.38 0.057
24 60 3.18 0.076
26 65 4.25 0.102
27 67.5 6.75 0.162
27+ weigh Koi weigh Koi
