Posted by TFH Magazine in Tropical Fish Hobbyist Blog on December 8, 2009 at 7:33 am
By Ted Judy
There are many species of tetras, barbs and danios that are not difficult to spawn. A good rule of thumb to figuring out a species’ difficulty is to compare prices at a fish store. Fish that are common and inexpensive are most often farm raised and easy to breed. The poster-fish for this group is the zebra danio Danio rerio. There are two challenges for the hobbyist breeder when working with these species. First, collecting the eggs can be impossible if the breeding tank is not set up to catch eggs. Second, raising the very small fry can be a challenge without the right foods ready when they are needed.
I breed most of the tetras, barbs and danios in 2.5 gallon tank. When the fish are very small, and lay a lot of eggs, I usually put a lot of yarn mops in the tanks. After a few days the fish have deposited plenty of eggs in the yarn. Some will get eaten, but there are enough hidden in the mops to meet my modest requirements (I do not really need or want more than a dozen fry). Larger species tend to be better at eating their eggs, so I use a false bottom in the tank made from a piece of plastic needle-point mesh cut to fit into the 2.5-gallon tank. I cut the screen so that it drapes in the bottom. I use a couple pieces of PVC to hold the plastic off of the glass.
Once the screen is in place I add plants or yarn as a place for the fish to spawn. The eggs filter through the plants and then fall through the plastic mesh. Since the bottom of the tank is bare the eggs easily seen. After the eggs are laid I remove the fish, screen and pvc. I leave the plants and add a drop or two of methylene blue. I cover the top of the tank with a piece of cardboard to block the light. Most species’ eggs hatch in less than three days, and the fry are ready to eat a day later.
The first food I use is paramecium. If you do not have a paramecium culture there are products on the market, called fry foods, which are designed to provide small particles for baby fish. A good supplement to a food product is ‘sponge grunge’. Squeeze a well established sponge filter into the tank with the fry and some plants. The microorganisms in the sponge will start a colony that will feed to fry. After a few days the fry can eat microworms. One trick I use is to keep my microworm cultures very wet, about the consistency of a thick soup. The media in the culture contains all different sizes of the nematodes. When I feed from the culture, I scoop a little of the media onto my finger and swirl it into the tank with the fry. Yes, it clouds the water… but the fry do not care, and they are getting very small food.
After a week most fry can eat baby brine shrimp and they are off to the races. With lots of food and frequent water changes they will grow fast.
I have ten 2.5-gallon breeding tanks in my fish room. From spawn to relocating the fry to a growout tank tanks about 10 – 15 days. If everything works out perfectly I could breed 20 – 30 species of ‘easy’ tetras, barbs and danios in thirty days. Plans rarely work out perfectly, however, and I am happy to be successful with 5 – 10 successful spawns each month.