Duncan Griffiths

Copyright © 2004 koi-unleashed. All rights reserved


Dystocia or egg binding is something you will experience from time to time with mature female koi.


This condition will be evident in mid summer although things started to go wrong as early as spring.


Seasonal changes and temperature play a huge part in egg development and maturity in carp. If a female is mature enough to spawn, this will usually take place as the length of daylight hours gets longer and temperature hits a trigger point about (20oc).

Although spawning can in certain circumstances take place in late summer if temperatures are not high enough in late spring.


The temperature not only needs to be 20o c or just over but this temperature needs to be maintained for a number of days for natural egg maturation to take place.


The ovaries need time to develop prior to spawning. If this does not happen, eggs will accumulate in the ovaries and will not mature. This process is continual so, even though the eggs are not mature enough to be spawned, more will be added as the season continues. This results in egg binding.


The natural spawning of carp is quite a brutal affair. It is not like salmon and trout where the eggs lie free inside the female and as she lays her eggs and the male just swims over the top and deposits his milt. The carpís eggís remains in the ovaries and have to be almost bludgeoned out of the female by strong contact from the male.


Several suitably large males will chase one female that is ready to spawn and the chase is long and hard. The end result is the male or several males cornering the female in a position where she cannot escape, and will more or less ram her in the side to expel the eggs from the female.


This has several implications. As the eggs build up in the ovaries, the koi has to carry this burden and in some cases infection of the ovaries can set in. This can be one complication in itself, but further; itís entirely possible the female will not be strong enough to survive the onslaught from all these amorous males. After spawning, both female and male can need some minor treatments to wounds and most definitely need time to recover.


A female that is egg impacted will be quite bloated, the bloating will be soft to the touch, becoming harder as the condition progresses.

This koi shows sever Dystocia the has undoubtedly Induced septicaemia

Picture kind courtesyof Spike Cover




In the event you need to intervene you can do one of a couple of things. If no signs of stress are evident, you can simply keep an eye on the female and let her go into the winter and hopefully if food is withheld, she will reabsorb their eggs as a food source. This can take up to two years. Alternatively, Ramp the temperature to 25oc and hold the female at that temperature for at least seven days. Try her every other day to see if she can be hand stripped of her eggs.


In either event egg impaction can lead to bacterial infection and septicaemia, and as well as the above treatments if you suspect infection may need to be supplemented with antibiotic injections.


If these two look an unlikely prospect, you will have to inject with carp pituitary extract. The following three hormones are only available on prescription:



CPE Carp pituitary extract


CPE is obtained from agricultural pharmaceutical companies via your friendly vet. Suppliers, obtain this hormone from the carp pituitary gland situated under the carp brain. It is supplied as a powder that needs reconstituting with sterile water or saline.


Injections are given at the rate of 0.3 mg/kg of body weight. 18 hours after, a second injection is given at 3 mg /kg. 10 hours after the second injection manual spawning can be attempted.


Care must be taken not to apply too much pressure to the abdomen of the koi to strip the eggs, as damage can easily result.If the eggs will come, they will take no effort at all; in fact, just lifting the koi may expel lots of eggs or spawn.


Two other hormones can be used for injections to induce spawning

Luteinizing Ė release hormone {LH-RH (a)}.


LH-RH (a) hormone comes in at a higher command level than pituitary and is the hormone that comes from the hypothalamus. The release of this hormone kick starts the pituitary gland into action.

5 mg/kg of body weight, two injections


H.C.G. Human Chorionic Gonadotropin


As the name implies, this originates from humans and can be used to spawn fish. H.C.G. is at a lower command level than pituitary extract and is the hormone (Gonadotropin) that the pituitary gland excretes to stimulate ovaries and testes to mature. H.C.G. is highly recommended and is cost effective for koi that are ripe to spawn.


800 IU/kg body weight, where IU = micrograms


1 gram = 1000 milligram; 1 milligram = 1000 micrograms; 1,000,000 micrograms = 1 gram.