I understand most zebrafish groups use Artemia nauplii as live food, due to the ease of hatching large batches of commercially available eggs and reduced risk of contamination with infectious agents. The downside is Artemia don't survive in freshwater and overfeeding can lead to water fouling. Daphnia are often mentioned as a possible alternative, usually as a sidenote. I suppose this is because Daphnia cultures maintenance is more work demanding than hatching Artemia, size selection requires sieving and productivity is not efficient for medium/large facilities.
If live food is required in small quantities, would a controlled Daphnia culture be a worthwile alternative to Artemia naupli?
You can maintain adult artemia culture system between 60 to under 100 parts per thousand (for San Francisco Bay strain) wherein they will issue out plenty of nauplii, which can be filtered from the tank & segregated.Freeze them in small blocks & use it as feed when needed.It is essential that the salinity of the adult artemia culture tank is not altered by + or - 5 ppt/day.In this way.Artemia nauplii being bright pink in color,they will be easily seen by the consumers.It's better not to overfeed the consumers so as to avoid turbidity,for hunger to a small extent is tolerated by the consumers.Rice bran extract,whey powder suspended in water are some of the types of feeds that can be used for adult artemia culture systems.
Artemia has a one micron thick exoskeleton & no bristles which compares well as compared to Daphnia.The latter being almost transparent,it at times makes it difficult to segregate adults from juveniles.Preparing feed for artemia is easier than for daphnia.
Not having used daphnia before, I cannot speak to the culturing complications related to this substitute, or the impact on water quality the over feeding of it may cause, however I can attest to the fact that artemia nauplii can be effectively substituted.
At the end of last year we did away with the production and use of artemia as a live food for our fish, primarily relating to costs. However in order to be able to remove this costly component from our feeding regime, we needed to ensure that fish health and survival would not be negatively impacted.
We discovered that the artemia was most crucial for the fry transition development phase of the culture (when the zebrafish larvae are between 5.23-11mm standard length). At this stage the fish are still fussy eaters and seem to require a heightened level of stimulation to engage with their food than a standard cluster diet can initiate.
We discovered that extending the feeding of rotifers (Brachionus plicatillus) to the culture beyond the standard polyculture phase (3-6mm standard length) made for an effective substitute to the use of artemia. The rotifers provided equal growth and survival rates to the use of artemia, but is cheaper to culture and doesn't result in a risk of water fouling in your slow drip nursery tanks.
As a result, we now rear our zebrafish culture entirely on rotifers and cluster diet, with rotifers being fed up to the fingerling transition (11mm standard length) by which time the fish have developed sufficient gape widths to manage appropriately sized cluster diet, and they are more engaged feeders, responding directly to the supply of feed rather than looking to graze.
Providing that daphnia are easy to culture, the fact they too are a gut loadable zooplankton, there is no reason to believe that they could not be substituted in a similar manner.
yes we use rotifer and we find them easier to culture and good size for newly hatched larvae. some fish get blocked guts if they consume un-hatched egg or an empty egg shell. brine shrimp after instar I they have to be enriched otherwise their nutritional value is less. Daphnia are easy to culture and Moina species such as (Moina micrura) are the small verity which suites smaller fish and they are salt tolerant.
I have reared zebrafish for 7 years. I don't have experience for rotifer but I have used the commercial powder. It's very small size, 0~30um. So it doesn't need any work. The surval rate of larvae from 5dpf to 20dpf reaches at least more than 80%. I feed artemia from 15dpf to adult.
Dear Kurwie
Artemia are supplied in dried eggs. I just incubate them with salt solution for 24 hours (someone says 18hours ~24hours) for getting hatched ones. No enrichment is better for yolk consumption.
We sometimes fed daphnia to fish but rather for them to have some variation in food than a real food. You also need to be carefull not to contaminate your fish stock by daphnia. I would not recomend excjangim daphnids for artemia. Daphnids are not so nutritios and fish do not grow so fast and do not produce so many eggs.
hi
Article An Update on the Global Stressors and Constraints Affecting ...
you can now find all what you need for rotifer culture in EU : www.planktovie.biz
Also, I really recommend the use of live feed for at least the 1st 5 days of exogeneous feeding. More and more labs are now using live feeds until 60 dpf : Article Toward an Integrated Zebrafish Health Management Program Sup...
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