I would say that test tubes are a bad idea and that the lysed eggs are probably due to the small water volume and surface to air ratio. Changes in temperature and poor gas exchange, will kill the eggs, dead eggs will pollute the small volume instantly. The larger the volume of water and air the better, the smaller you go the worse off you are. The same volume of water in a petri-dish would probably fair better as the surface to air ratio would be improved. I think fish bags filled half way are better. When I was a teen I worked in a pet store for many years and I noted that transportation deaths of fish in plastic bags were directly related to the amount of air space available and temperature. Interestingly enough double bagged fish died quicker than single bagged fish. I am assuming the double bagged retained more heat.