Fish laying eggs?
Many times fish keepers are caught by surprise and your fish may have already laid eggs. If you are lucky enough to have a male and female that have bred in the aquarium then you most probably want the eggs to hatch to become baby fish. This may be difficult if the fish lay eggs in a community aquarium. If the fish are cichlids they will look after their eggs and young to some extent. Remember other fish will want to eat the eggs and baby fish if they get a chance. If you want to maximise your chance of raising the baby fish then it might be a good idea if you carefully removed the other fish. Note that disturbing fish with eggs or young may result in the parents killing their offspring.
Fish such as angel fish, kribensis, or convict cichlids are the most likely to spawn with out ay help from you. And as often as not they will spawn in the community aquarium.
How To Start Breeding Egg-Laying Fish: A Guide To Egg-Layers
If you have already enjoyed some success breeding livebearers such as guppies or platys then your next step could be breeding egg-laying fish. These fish can be a bit more of a challenge in producing healthy young successfully, but are well worth the effort.
With the success of breeding live-bearing fish, you should already have most of the equipment and expertise necessary to make the step up to breeding egg-laying fish. So how do you complete the next step? What do you need to know and do? You need to provide the right water conditions and the appropriate spawning environment for the adult fish. Then you need to feed and raise the young which are usually smaller than livebearer fry.
Choosing Your First Egg-Layers
There are many egg-laying fish species that breed in one of several ways. In order to maximize your chances of success, it is recommended that your first egg-layer be either a simple cave-spawner such as kribensis or convict cichlids, or easily cared for egg-scatterers such as zebra danio or rosy barb.
Egg-laying fish that protect their young are relatively easy to spawn plus they look after their eggs and fry: The optimal conditions can be reached by raising the water a few degrees, feeding well with live food such as blood worms, and providing a cave-like structure or spawning stones somewhere in the tank.
Kribensis, for example, will seek out a cave or other similar hiding place when ready to spawn. The female will lay her eggs in the cave and let the male fertilize them. For the next week or so, they will both guard the nest from other fish.
Setting Up The Right Conditions For Egg-Layer Spawning
The first thing to take into consideration for breeding egg-laying fish will be to set up the correct temperature for spawning. Every species of fish has different needs, but there are a few universal principles that will apply to keep the eggs and fry safe; one of these is the use of a separate breeding tank.
Fish eggs and fry are largely considered fair game for hungry adult fish—including the parents of some species. For this reason, you will need to setup a breeding tank in order to prevent other fish eating the fry. Also a breeding tank has space for your fry to grow.
Another overlooked danger for eggs and fry is your filtration system. Eggs and fry are so tiny that they can easily be sucked into the filter where they will be crushed. Your breeding tank will need to use a low flow sponge filter in order to keep the eggs safe at least for the first week or two.
In the case of egg-scattering fish such as the Zebra Danio, it is recommended that both adults are removed immediately after laying is complete. Installing a layer of marbles or a porous net as a substrate can help protect the the eggs which will fall between the gaps where they cannot be reached or eaten.
Successfully breeding egg-laying fish also requires more attention to the water quality and feeding. Clean tank water encourages breeding, and often the most difficult part of breeding is maintaining the correct balance between high quality water and high levels of food. Many fish will only breed when given very clean water and live food.
How to recognise if your fish are breeding
When the female is noticeably plump and the male is more vibrantly coloured then you can be sure the fish will soon spawn. With brood carers such as kribensis and convict cichlids you will notice mouth wrestling between the pair. Also they will flirt with each other by waving their bodies and fins at each other. With egg scatterers you will see flirting and chasing. When the fish spawn they usually quiver their bodies as they lay eggs and release milt.
Caring For Your Fish Eggs And Raising Fry
If you have managed to get your fish to breed, and have a number of fish eggs waiting to hatch in your breeding tank, it is time to focus on keeping them safe until hatching and then providing the fry with everything they need to grow into healthy adult fish.
Once your eggs are safely deposited in the breeding tank and out of reach of any other fish, you are ready to begin the waiting game. With very clean water and an appropriate temperature, you should begin to see fry appear within a few days or so.
However, do not feed the fry when they first hatch. They will not feed. And are not yet free swimming but just dart about occasionally. Fry when first hatched still have a yolk sac attached which they feed off. When they have completely absorbed the yolk sac, they will then start eating and start free swimming. They need to be fed at this point. This is where most beginners fail.
When breeding egg-laying fish, it is often necessary to feed your fry live food—the problem here, however, is that many of these fish are too small to eat many commercially available live foods. The best foods for these tiny fry are infusoria, which have to be cultivated beforehand. After a week or two depending on species they will be big enough to eat baby brine shrimp and microworms. After 1 month they can then be fed on crushed dry food.
In order to encourage the growth of your fry, frequent feeding and water changes are recommended: Your fry should be fed lightly several times per day, and at least 10% of the water changed every other day.
Considerations For Fish Nearing Adulthood
If your first experiment in breeding egg-laying fish has gone well so far, you should have a small breeding tank full of young fry that are rapidly growing. But you will soon have to make space for the young adult fish to move into.
If you have a breeding tank of 50 litres that is housing perhaps a 100 young fry, you will not be able to keep them all there for very long. If you already have a network of contacts to whom you can sell your or swap your young fish, then you should be able to sell them off relatively quickly, but it is important to have extra tank space ready just in case. If needs must then you can try offloading some at your local petstore.
If you have prepared a separate tank for the adults to live in, you will be able to successfully transfer them there when they are adults and begin selling them off without pressure. Nobody wants to spoil all of this hard work at the last step because there is no room for an otherwise successful attempt at breeding egg-laying fish.