By Michael B. Rust
School of Fisheries, WH 10, University of Washington, Seattle, WA 98195
Spawning Zebrafish in a Net Bottom Bucket
Zebrafish can be spawned in containers that have had their bottoms cut out and replaced with 1/4" or 1/8" black plastic netting (Vexar works well). We use 2.5 gallon plastic buckets suspended in clean temperature-controlled 10 gallon aquaria.
The eggs drop through the net to the bottom of the aquarium. Because there are no marbles, the eggs are easy to remove. The adults stay isolated from the eggs so they are also easy to remove. We have used a second bucket (with a solid bottom) around the net bottom bucket to harvest eggs.
The eggs are then incubated in a plastic 750 ml bucket which has had the bottom removed and replaced with a 250 um nitex screen. Incubation containers are suspended in an aquarium with a heater and an active biofilter. The same container is used through the larval stage until fish are large enough to transfer out of the aquarium and be weaned onto flake food.
Zebrafish Larvae Don't Need Live Food:
Rearing Larvae on Commercial Diets
If you hate culturing paramecia for the first feeding of zebrafish larvae, why not use an artificial diet? We have had excellent results rearing zebrafish larvae entirely on a yeast-based diet made by Provesta Corp. of Bartlesville, OK. Their diet, called "Microfeast", is intended to be fed to Artemia and rotifers, but it works well on zebrafish larvae, too.
Artificial diets are messier than live diets, so we culture the zebrafish larvae in plastic 750 ml buckets which have had the bottoms removed and replaced with a 250 um nitex screen. A hot glue gun does a good job of attaching the screen to the bottom of the bucket. These buckets are then suspended in a heated 20 gallon aquarium with a well-aged biological filter. The diets are fed by an automatic feeder ("The Fish Sitter", available at large aquarium stores) that has been modified to feed continually through the daylight hours.
It is important not to overfeed larvae. The feeder will hold a lot more feed than is necessary. About 0.1 g/day is enough to feed 200-300 larvae in a 750 ml bucket. Daily maintenance takes about 15 minutes and consists of refilling the feeder and flushing the bucket with clean water to remove uneaten food and feces.
Marvelous Meaty Artemia Cookies
Instead of hatching fresh Artemia for your broodstock and juvenile zebrafish every day, your might consider making Artemia cookies and feeding these instead. First, hatch a big batch (about two weeks' worth) of Artemia.
After hatching, clean the shrimp in the normal way, rinse with fresh water, and then concentrate on a 100 um screen. (We use a 3" PVC connector with a Nitex screen sandwiched between the fitting and a short length of 3" pipe.)
Pipette the normal ration of Artemia for a tank into the well of an ice cube tray (plastic ones that make small cubes are best). Repeat until you run out of Artemia or tray space. Add fresh fish water to fill the trays and freeze.
When it is time to feed the fish, just pop out a cookie (ice cube) and add to the tank. The ice will slowly melt and release the Artemia, feeding your fish. You can do the same thing with any fresh material such as worms, fruit flies, or liver paste.
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