Page Comparison

(Source: S. Russell from Zebrafish Book 5th Edition)

Fish and marbles

At the onset of the light cycle, zebrafish will generally initiate breeding behavior that results in the laying and fertilization of eggs.  In a tank that has been marbled, the eggs collect between the marbles and escape predation. However, when no marbles are in the tank, the fish will rapidly consume the eggs.  By eating the eggs, the fish are cycling the protein within the tank, reducing the energy loss experienced in egg production and breeding behavior.  By marbling a tank, the egg protein source is denied and energy loss to a tank is extensive, which is why fish should be put over marbles no more frequently than once per week.  On days when the fish are not over marbles, they should be fed several times per day with protein rich foods to compensate for their energy loss.

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Siphons are to be used only once.  When finished with the siphon, sterilize it by bleaching and rinsing.  Never use a siphon in more than one tank.

Removing marbles from a tank

Marbles should be removed from tanks promptly. After siphoning, use a net to remove the marbles.  Clean them with bleach and extensive rinsing.

Cleaning marble eggs

Clean eggs obtained from marble tanks either by rinsing with clean system water to wash away debris or by removing the debris with a pipette.  To rinse, pour off dirty fish water with as much of the loose debris from the eggs as possible.  Add clean system water and repeat the process.  With each addition of clean water to the eggs, the debris is diluted and suspended in the water so that it can be subsequently poured off. Repeat this process three to six times.  Finally, use a pipette to remove any remaining debris.  This method is quick, but often does not completely free the eggs from debris. In addition, eggs can sometimes be lost while pouring off the water.

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Fish used for embryo production over marbles are for the most part reliable at egg production until they are about 2 years old.  Generally, marble fish consist of 8 females and 4 males in a 10 gallon tank.

Feeding marble fish

Because fish producing eggs over marbles expend more energy than regular stock fish, it is important to provide them with a diet that compensates for the energy lost in egg laying and breeding and that is ample enough to allow the fish to develop the reserves from which new eggs will be produced and nourished.

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Example of Feeding Schedule