Steps of propagation
These steps are by no means fixed. In fact new ideas are emerging constantly.
The African catfish could be propagated in several ways. These ways are basic, though dynamic.
Step 1: Identify and separate the sexes.
The male and female of the African catfish can be easily recognized. The male has a distinct sexual papilla, elongated and located just behind the anus. This sexual papilla is usually red at the tip for sexually ready males. It is absent in females.
A gentle press on the belly of the female fish towards the genital opening releases the ripe eggs indicating the readiness and viability of the female.
A sexually ready female has a swollen, usually reddish genital opening. A view from the top also gives a female African catfish away since either side of the belly appears swollen.
Step 2: Select and check for a gravid female ((i.e. female with ripe eggs)
Step 3: Weigh the Female Fish
Put the pituitary inside a laboratory mortar.
Grind the pituitary using a pestle until it becomes powder.
Add 1ml saline solution.
Collect the solution and Inject the female fish using an hypodermic Syringe.
This is done to have an idea of the weight of the egg inside the fish.
A female catfish that therefore weighs 500grams has the weight of the egg to be 50 grams.
A gram of egg contains approximately 700 eggs.
Thus a gravid female African catfish with a weight of 500grams could boast of 35,000 eggs.
The viability of the eggs depends on brood stock care and management.
Step 4: Prepare the female Catfish for injection
African catfish pituitary is commonly used for induced catfish breeding. Methods of removal and preservation of the pituitary are not contained in this book.
For induced breeding of the African catfish, I like to the use the pituitary gland, either freshly removed or ethanol preserved. I recommend a ratio of 1:1, recipient: donor i.e. if the weight of the female fish to be induced is 1kg, the weight of the donor fish, male or female should also be 1kg for freshly removed pituitary.
However, for dried, preserved pituitary, I recommend a ratio of 1:1.5 i.e. recipient fish should be 1kg and the donor fish should weigh 1.5kg. I will like to state here that it is not compulsory that the donor fish should be one fish; it could be 2 or 3 fishes with a combined weight of 1.5kg or as the case may be in weight.
A synthetic hormone can also be used. Usually, the manufacturer will include the prescribed dosage suitable for The African Catfish breeding.
When you want to inject the fish, please don’t inject the fish on the lateral line. I personally prefer the syringe pointing towards the tail of the fish. The fish should also be injected above the lateral line with the needle at 45 degrees to body of the fish.When you want to inject the fish, please don’t inject the fish on the lateral line.
Preferably, the syringe should be pointed towards the head of the fish. The fish should also be injected above the lateral line with the needle at 45 degrees to body of the fish.
Note that this process should be done while the fish’s head is covered with a moist towel. This allows the fish to remain calm throughout the 18 entire process.
Step 5: Isolate the Injected fish in a Comfortable, big bowl and wait for 10 to 12 hours.
Step 6: Prepare to strip the fish, Set up your incubator.
Step 7: Bring the Fish out after 10 to 12 hours gently and cover the head with a clean, moist towel.
Step 8: Wipe the body of the fish dry using a dry, soft towel.
Step 9: Strip the fish (i.e. press the eggs out of the fish).
The pituitary injection makes the fish ready to release the eggs. In fact after the injection has been administered to the fish, following the right dosage, the process of getting the eggs out of the fish is irreversible.
Step 10: Weigh the stripped eggs
This helps to have an idea of the expected fry.
Step 11: Bring the Male out, kill it, turn the belly up and cut it open
Step 12: Remove the milt sac
Step 13: Cut the testicles into bits to release the sperm
Step 14: Add saline solution to the milt
Step 15: Pour the mixture of saline solution and milt to the stripped eggs in the bowl
Step 16: Mix thoroughly and add fresh, clean, water
The Saline solution added to the milt (sperm) keeps the sperm alive but not active. The saline solution makes it easy for the entire stripped eggs to be saturated with the milt. The subsequent addition of fresh, clean water now makes the sperm active and motile.
It is the addition of clean water that initiates the external fertilization process. This whole process of fertilization lasts for only about 60 seconds. That is why I strongly advice that you increase percentage fertilization by stirring the mixture during this 60 seconds.
Continue mixing to prevent eggs from sticking together.
Step 17: Spread the eggs inside the incubator on the Spawning sponge
The spawning sponge is completely immersed in water. It however sits on the spawning net which keeps it suspended in the water. The net is held in place by pegs.
Step 18: Wait 20 to 36 hours
After 20 to 36 hours, remove the sponge and spawning net. By now the fry would have emerged from the hatched eggs and would have gone to the bottom of the net.
The un-hatched ones, now attached to the spawning sponge and spawning net are removed from the water since they would be attacked by fungi if left for too long. This fungi would inevitably attack the hatched eggs at the bottom of the net.
Step 19: Observe the newly hatched eggs, with yolk still visible and attached to the fry