RAISING CLOWNFISH
BY CHAZ STEVENS AND JENNY BRADLEY
(c) A Midlands Marine Aquarists Society Article - 4 Nov 04
See Also: Clownfish
The following is a day by day account of the method currently used to raise common clowns and black and white clowns.
Hatch night. The larvae tank, 18”x 10” x 10” is part filled (5” deep) with either water from the parents tank, or newly made salt water, it does not seem to make any difference to the
hatch rate. To this another gallon of fresh water is added, this brings the s.g. down to around 1.018, this makes the eggs denser than the surrounding water, they then have a tendency to absorb the surrounding water and have a better hatch rate. the newly hatched larvae also exert less energy maintaining there osmotic pressure and so seem to survive better.
The pot with the eggs attached is placed in the larvae tank with an open air line placed by the egg mass producing a strong air flow passing over the eggs. the top of the larvae tank then has a piece of egg crate placed on it, and a piece of A4 paper placed on this. this is the light diffuser which will be kept in place for the next 10 days. The whole of the
tank is then covered with a bin liner to totally block out any light and the eggs are left too hopefully hatch.
Day 1
On the morning of day 1 the bin liner is removed and the air supply stopped. This allows you to see if the hatch took place. Hopefully the larvae tank is full of hundreds of 3mm long larvae swimming aimlessly through the water. If this is the case the pot that had the eggs on it can be removed and the depth of water in the tank can be reduced to around 2”
deep.The air supply is turned back on, this obviously airates the water and also helps keep the rotifers and algae in suspension.By reducing the amount of water in the larvae tank you greatly reduce the number of rotifers needed to feed the larvae. For the first 3 days you do not actually feed the fish as such, you feed the total volume of the tank. The
larvae do not actively hunt for the first 3 days, they just drift around and bump into the food items, so enough food has to be in the tank at all times to ensure they do not starve to death. At this time we also add live phyto plankton, the food item for the rotifers. This does 3 things, it keeps the rotifers well fed so that the larvae have an optimum diet,
the algae burns up the ammonia and nitrites produced by the larvae and rotifers, and the larvae actually swim around in the water column better because side lighting is reduced, which means they do not “climb the walls”, swimming against the side of the tank, looking at their own reflections and not feeding. Twice a day the rotifer density is checked by
immersing a small glass into the larvae tank and simply looking how thick the rotifers are. If the rotifer concentration is too low the larvae will starve. Rotifers are added as required for the first 7 days. The live phyto algae density is also maintained on a twice daily basis.
Day 2
The first water change takes place today and this procedure is followed every day until the larvae tank goes onto the “mini system” usually around day 10. Water is removed from the larvae tank by simply syphoning through a rotifer sieve that has been immersed in the tank. this leaves the larvae and rotifers in the larvae tank. Freshly made salt water has a
few drops of iodine added to it and is placed in a 5 litre ice-cream tub. the ice-cream tub is placed above the larvae tank and a syphon is made using air line, the new water is then allowed to top the larvae tank back up to its required level. Note, the water level of the larvae tank is increased as the larvae become more active and hunt more efficiently.
The water changes and use of iodine appears to improve the striping up of the larvae, we now get 95% of common clowns with perfect stripes, but still only get around 60% of black and whites with perfect stripes! We are at this moment experimenting, carrying out 2 water changes per day on the latest batch of black and
whites to see if this improves the stripes. Jenny’s theory is that if the black and whites grow and stripe up quicker than normal clowns it may be that they absorb more of some unidentified substance out of the water, or that they simply produce more pollution that impairs the water quality, we shall see!
Day 3
Day 3 is basically a repeat of day 2, water change, add rotifers and algae.
Day 4
By day 4 the larvae have grown enough to be able to take freshly hatched brine shrimp, as well as rotifers. At this time we also start introducing very fine powdered foods. dry foods are fed 3 times a day, always before the live foods, to encourage the larvae to take dry foods.
Day 5
As day 4
Day 6
As day 5, but rotifer concentration may be allowed to start to drop as hopefully most of the larvae should now be taking the freshly hatched brine shrimp and powdered food. the water level should also now be back up to the 5” or 6” deep level as the larvae are now far more active. The live phyto level can also be reduced as the rotifers are no longer in such
large numbers. The egg crate and paper light defuser must still be in place.
Day 7
By this time the black and white clowns may be showing their first stripe, the head stripe. For some reason the black and whites stripe up earlier and grow faster than the common clowns. The larvae will now be taking 24 hour old brineshrimp as well as freshly hatched brineshrimp. You always overlap different food items and sizes
to allow for the slower developers. We use brineshrimp of different ages for two reasons:
1. Its physically bigger, a more substantial food item.
2. Because the 24 hour and 36 hour brineshrimp are now actually feeding themselves on algaes, they become a more complete food item, meat and veg. this is the time when we also start to get the larvae used to feeding on Koi sticks, these are allowed to float in the water until soft and then crushed up into a fine
particle cloud, the larvae swim into the food cloud and feed, over the next few days the larvae will learn where the food cloud comes from and start feeding on the floating Koi sticks!
Day 8
As day 7
Day 9
By today the black and whites will have the second, mid body stripe.The larvae or more correctly the juvenile fish will now be taking 36 hour old brine shrimp along with 24 hour and freshly hatched brineshrimp.
Day 10
The mini system.
The larvae tanks that we use all have a hole in the one end which allows us to fit a ˝” outlet pipe to the tanks. on the inside of the tank a sponge strainer is fitted and on the outside of the tank pipework is fitted that feeds a sump. The sump contains a skimmer, internal power filter and air diffuser. A small pump in the sump feeds a small U.V. and then
pipework and taps control the flow back into the larvae tanks. On day 10 we usually go onto the mini system, no more water changes. By day 10 we are also feeding crushed flake food, as well as powdered food and Cyclop-eeze.
Day 18
By day 18 we have normally got the juvenile fish totally off any form of brineshrimp. You cannot move fish that are still being fed on brineshrimp; they go into shock and die! The tank is now taken off the mini system and joined onto the grow out system. The tank is fed by an air line syphon tube from a tank above it and it overflows into a tank
below it. this allows the juvenile fish to get use to the water quality in the grow out system prior to being moved into it.
Day 20
This is the time we usually move the fish into the grow out system, just net them up and place them in their new home, no need to acclimatise, they have been swimming in the water for the last two days! Clean the tank using cold fresh water, no sterilising, and start again. that’s all there is to it if it all goes right!!!
