Shipping Killifish Eggs

The killifish hobby survives on the international trade of eggs among hobbyists. Naturally the question on how to ship eggs is raised very soon after a new comer enters the hobby. Much of the information that is learnt and spread was acquired by trial and error and that is how you too will learn. What follows is a summation of how I do it and a few deviations as to how other people do it.


With most non-annuals, one is working with a 10 to 14 day window to get the eggs through to their destination. With the Chromaphyosemion 10 days is all you have while with some of the cooler living killies and semi-annuals 21 day incubation periods are the norm.

I have tried to ship non-annual eggs in water and peat with little success. The main problem with the water was that often one or two eggs would die and foul the water killing all the other eggs. Adding antibiotics and dyes often killed more eggs than they saved. Acriflavine was one such dangerous drug. Acriflavine, if given at too high a dose or left too long with the eggs, can harden the chorion of the eggs and kill the embryo. The main problem with peat is the tendency of the wet peat to turn anaerobic if too wet or dry the eggs out if too dry. To over come this Bill Shenefelt ships eggs in fibrous peat (like what is sold as Fluval filter media) in Kordon breathing bags with great success. If the peat is handled right the incubation time can be extended many weeks. It is not a good idea using a course peat such as coconut palm peat as the hard sharp pieces of coconut husk can damage the eggs.

The best method is to spawn the fish over peat or let them spawn in peat and then removed the peat and allow the excess water to drip from the peat. Do not squeeze the peat! If you cannot entice the fish to spawn in peat then you will have to pick the eggs off mops and put them in peat. The best method in this case is to pick the eggs and place them in water and then pour the eater and eggs into damp peat. Allow the water to drip from the peat and then pack the peat and eggs in a plastic bag and post them. It is important to insulate the peat using styrofoam. Kenjiro Tanaka constructs small styrofoam boxes out of three pieces of styrofoam. The pieces are stacked one on top of the other. The middle pieces is hollowed out so as to be a frame fitting round the egg parcel. The entire package is then taped up.

An example from my peat incubation experiences is as follows:

Species water (average) peat (average)
A. australe 14 days 4 weeks
Aphyosemion lamberti 14 days 4 weeks
Aphyosemion punctatum 14 days 4 weeks
Aphyosemion elberti "Diang" 21 days 4--5 weeks
Fp. g.gardneri "N'Sukka" 21 days 6 weeks
Chr. bivittatum "Funge" 12 days 4 weeks
Chr. poliaki "Bolifamba" 12 days 4 weeks
E. dageti monroviae 10 days 3 weeks


To ship eggs in water I use eppendorf test tubes (figure above) filled to the 0.5 ml mark with a half strength solution of Tetra General Tonic (half the recommended dose) prepared in the water of the tank the eggs are coming out of. The solution and an egg is pipetted into the eppi and then closed. This method has the virtue of egg quarantine. Even if some of the eggs die they don’t harm the rest. In addition, if by some chance the eggs hatch in transit the fry can survive for a day or two and if it succumbs it will not hinder the survival of the rest. I have had good success with this method both in shipping eggs and receiving them.

Another method is to ship the eggs in film canisters. The canister is filled with a solution of Tetra Genral Tonic as above to about 1/10th full. Some threads of yawn or cotton/filter wool is put into the canister and the eggs are placed on top of this. Another piece of material is placed on top of this and then the canister is sealed. I have not yet tried this personally but eggs I have received in this manner have always been in good condition.


It is never wise to ship annual eggs from a region of one temperature extreme to an area of a different temperature extreme. The best times to send eggs are spring and autumn. In addition, some annual eggs don’t respond well to air travel. The changes in pressure and temperature can cause massive egg loss. It is also best to send fresh eggs not yet showing any sign of development.

I use bubble wrap lined envelopes. The eggs are sent in thin plastic bags where some oxygen exchange can still occur but no water loss. The bag of eggs is flattened to make it as thin as possible and puffed up with air to buffer for pressure changes. This bag is placed in a small styrofoam box and shipped within the padded envelope. 

It is important not to send just a styrofoam box as this can be damaged in transit and contents spill out.

Certain states have regulations regarding the importation of soil (even peat) in fear of introducing nematode worms that could cause crop damage. It is best to check local regulations when planning to ship eggs and take into account for these regulations. Either label the packet as containing a sterile soil sample or some other creative but believable label. It is best not to misrepresent the contents however as the packet may be searched especially if instructions are written on the envelope for it not to be X-rayed.

The topic of X-ray damage is debatable. Given the large bulk of mail going through post offices it is unlikely that the package will be exposed to large direct dose of X-rays. Given the sensitivity of photographic film to X-rays it is doubtful that the X-rays used to scan contents could damage the developing embryos as it does very little to photographic film.

I hope this information was of use. If you have a difference of opinion please email me so it can be included. This page doesn’t print well so if you want to print it click here for a copy you can print.

Received eggs should be expected on arrival by the buyer and complaints registered promptly for two reasons:

  1. Eggs sent by post (particularly where temperature changes are involved) may develop abnormally. Some may develop very fast and if the buyer does not monitor the development by the time he wets the eggs the eggs may have long ago died.
  2. If many people have been sent eggs and the same problems are occurring then the error may well be on the sender's side and then by right he should replace the eggs (unless the receiver has assumed all responsibility). If the receiver only complains some months after arrival the fault could be anybodies...

For the above reasons it should also be obvious that egg development should be carefully monitored on at least a monthly basis.

Last updated 20 November 2006