by R. Shane Linder
The leopard danio is one of the most common danios found in pet stores. The fish is an overall metallic gold with blue-grey spots along the flanks. The scientific status of the leopard danio has been in question for many years. Some experts wonder if the fish is a true species or just a form of the zebra danio, Brachydanio rerio (Hamilton, 1822). The debate over the validity of this species has been in the aquarium literature for years. It would certainly be a worthwhile research project for an aquarist to look through the scientific and aquarium literature and put this debate to rest.
The leopard danio is a pretty fish that grows to just over 2" in length. The fish does not harm plants and gets along fine with just about any tankmate. The fish school about the upper waters, which is nice because close to the light, their gold bodies are very reflective and make a nice display.
I conditioned five fish, one male and four females, in a ten-gallon tank for two weeks. The tank was at 78 F, pH 7.6, and had a general hardness of 140 ppm. The fish were fed Tetra Bits, frozen brine shrimp and frozen bloodworms. The male and the two most gravid females were then moved to a 5-gallon tank for spawning. The spawning tank had a sponge filter, lots of Java Moss, and a substrate of dark marbles. The marbles trap the eggs and keep the ever-hungry parents from consuming them. With the marble substrate, it is possible to breed the fish in the same tank for up to a week. This is because even after the fry hatch, they lay at the bottom for four to five days, absorbing the yolk sac and remain protected by the marbles. The spawning tank was a mixture of 70% rainwater and 30% tap water. The temperature was 82 F, pH 6.8, and general hardness 60 ppm.
The parents were placed in the spawning tank 17 January 1999 in the evening and removed the following night. After hatching, the fry were separated among a 20 long and a 10-gallon tank. The fry survival rate was not very high, because these tanks already held pearl danio fry that were two days older. I believe the pearl danio fry outcompeted all but the toughest leopard danio fry. Now, almost one month later, the leopard danio fry are all about 1/4" long. They were raised mainly on Liquifry and smashed-up dry food with occasional live baby brine shrimp. At their current size, the fish are very pretty. The body is still clear, but the eye reflects a brilliant blue reminiscent of the neon tetra. One interesting observation is that for the first two to three weeks, the fish only feed at the surface. After this time, they search all levels of the tank for food. I have noticed quite a growth spurt in conjunction with their new method of searching for food. Although their older cousins, the pearl danios, certainly ate most of the food offered, I would estimate that after one month, I have nearly 100 fry.
This article first appeared in PVAS’s Delta Tale, Vol 30, # 2-3