Continued from page 1

Before attempting to breed your rainbowfishes, you should have been feeding them with the best food you had available for at least two preceding weeks. Commercial flake and pellet feeds will be suitable for most species, although they will all benefit from the addition of live and frozen foods such as bloodworms, daphnia, freshwater shrimp and mosquito larvae. Feed at least twice a day but making sure you don't overfeed. Also to increase your success try separating the males from the females during this two week period. Choose your breeders and place them in their breeding aquarium. This could be a well planted aquarium if you want the fry to hatch out and grow up in that aquarium. Otherwise, if you are going to collect and hatch the eggs separately, then use a basically bare aquarium and provide them with spawning mops.

Spawning mops can be easily made from acrylic thread (about 8 ply) cut into lengths of 30 cm and tied together in the middle. The mops can be attached to a piece of styrene foam and floated in the water or alternatively, just drop the bundle of loose thread into the aquarium. For a more natural appearance, you could use green coloured thread to simulate aquatic plants. Before using any spawning mops for different rainbowfish species, make sure that they have been sterilised to destroy any eggs or bugs which may still be attached to the mops. The females of many rainbowfish species are very similar and this will prevent the carryover of eggs, possibly resulting in hybridisation, or the transfer of disease from one breeding set-up to another. This is where spawning mops have a significant advantage over live plants in a breeding aquarium. All that is left now is to watch and wait. If you used a planted aquarium you will have to keep a close eye on the breeders and when you think they have spawned, which should be within 24 to 48 hours, you will have to remove them.

Despite what you may hear or read, most rainbowfish will eat their eggs, maybe not all of them, but they will certainly eat what they can find. I have seen the rare occasion where a male will attempt to keep all the other fish away from his spawning site and eggs, but generally it doesn't work too well. However, I have never seen a rainbowfish that doesn't eat fish eggs. If using mops they should be checked twice a day, morning and night. Just remove the mop, and, with most of the water squeezed out, inspect it for eggs. You can either pick the eggs from the mops or just exchange the mop for a new one. Fertile rainbowfish eggs are very firm and can be removed from the mops with clean fingertips. If you exchange mops, then you can just place the mops into the raising aquarium for hatching. If you opted for the pick and hatch method then you will need hatching containers. These can be plastic ice-cream, margarine or some other sort of container. You can add some fungus inhibitor to the water to be on the safe side. Fully developed embryos display prominent eyespots, and are usually refer to as the eggs being "eyed-up". Incubation times for most rainbowfishes is around 6 to 9 days at 25°C .

Next comes the exciting part - waiting for the hatch. If you chose the planted aquarium or mop-exchange method, all you have to do is scan the surface of the water each day to see if any have hatched. If on the other hand, you picked the eggs then you need to collect the hatching fry from the containers and place them in their raising aquarium. Do this with reasonable care and make sure the water conditions of the hatching container and the raising aquarium do not differ too greatly.

All that is left now is to raise them. Rainbowfish larvae at hatching, have a reduced but still present yolk sac. Their swim bladder inflates within 12 hours and they remain in the upper 1 cm water layer where they start looking for food. Therefore you will have to feed them as soon as you can. Now you could have spent all your spare time trying to raise infusorians, those wriggly things that are impossible to see in that smelly water you had sitting on the window sill for the last two weeks or do it the simple way - buy some fry food.

There are a host of finely powdered dry fry foods available on the market. One of the best ones that I have found is OSI microfood, just use it dry and sprinkle it over the surface of the water. You can use one of the liquid preparations, but I find that liquid foods sinks rather quickly and rainbowfish need their food on the surface or just below. However, a few drops wouldn't hurt and it gives them something different in their diet. Hard boiled egg yolk, a standard from yesteryear, is another good food. Just wrap the yolk in a clean cloth and twist it down into a section of the cloth. Then all you have to do is swish it around in the water. Once you get them past a couple of days you can then get really professional and hatch some brineshrimp or feed them some of that microworm that you've been culturing. Most species will also benefit from a growth of algae in the rearing container or the addition of small amounts of green water (phytoplankton).

Remember that the fry have probably hatched over a period of days and when you change from a small food to a larger one, keep feeding the smaller food until you are sure that all the fry are eating the larger one. If you have a batch that differ greatly in size (you will often find that the smaller ones are females), you may find that you have to feed three different size foods if you wish to raise all the fry. Just a small tip here, keep your fish foods in a refrigerator after opening, they last longer. The continued growth and development of the fry will vary depending on species, temperature, water quality and feeding regimes.

~ Photo © Günther Schmida, Australia.

To contact Adrian R.Tappin

NetPets® Main Page

contact information Main Library Fresh Water Breeding

The Fish Center