A lot of people have been asking questions and are eager to find reasonable answers to why they record fry mortality almost every time in their catfish farm. Well, there are a number of reasons why your newly hatched fish die. In today’s post, we will x-ray some of the causes of catfish fry mortality and show you how to prevent feature occurrence.
We had earlier published content on the causes of catfish mortality which was basically for general knowledge, but we will focus only on the newly hatched (fries) in this post. Before we look into how to prevent catfish fry mortality let’s find out what leads to the mortality itself.
What is Catfish Fry?
Catfish fries are newly hatched catfish between 7-10 days. It takes a process of 7 to 10 days for the spawn to grow up to the fry stage. From this stage, the fish will grow to a finger size known as fingerlings.
Basically, fish are called fries when they have developed to the point where they are capable of feeding themselves. It takes a period of 1 month to rear fries in nursery ponds.
Causes of Catfish Fry Mortality
There are reasons why your fries die. Every fish farmer raising catfish, be it clarias, hybrid or any other species of catfish must first start out with the nursery pond before moving the fish into a standard pond(s).
The issue has been that the fries start dying while they are still in the nursery pond. The question is what is the cause?
- Inadequate Preparation of the Pond
Farmers’ inability to prepare their nursery posts before hatching has been one of the major causes of fry mortality in most catfish farms.
It has been observed that farmers, especially the new ones are always in a hurry to stock and for this many forget the preparation processes. Reasons could be their excitement towards the profit they must have projected in their minds or lack of knowledge.
For every set of fries you want to bring into a new pond, you must first wash the pond thoroughly should incase if there is the presence of algae, ammonia, or decayed faeces from the previous harvest. Meanwhile, the standard practice is to adequately prepare the pond by washing and neutralizing anything that could be harmful to your catfish fries even before the hatching process begins.
New tarpaulin and tank ponds are poisonous and death traps due to the chemicals used during their production. There is need to first wash off the ponds with either salt or dried leaves and allow them to dry before making use of them.
2. Feeding on the First Day
The newly hatched fish come with a transparent or whitish sack under their belly. I guess you must have seen such without knowing what they are for. If you have, let us know by making use of the comment box below.
Why do catfish fries have sacks under their belly? What is in the sack is food their body will make use of or absorb in the first days. So, feeding them when those sacks are still visible is overfeeding.
Overfeeding is one of the major causes of catfish fry mortality and how to prevent their death is to allow them to stay for at least the next 24hours before giving them anything. We had already discussed the implications of overfeeding in our causes of catfish mortality. Do well to read the article.
3. Uncovered Pond(s)
The reason for having your ponds 80% covered and netted is to maintain a dark atmosphere in the pond and to also prevent flies, lizards, birds, etc. from feasting on them.
You may ask why the dark environment? If you expose them to direct sunlight that early, it leads to a greater number of them going blind. Now you understand.
Since the catfish fries are very tiny, does overstocking the pond mean anything? Yes, a lot.
There are different sizes of ponds and wisdom demands that you know the capacity of your pond before you stock. Our guide on stocking concrete and earthen pond will show you the mathematics of stocking. To prevent catfish mortality, especially at the fry stage, you must first understand how to go about the stocking.
Few weeks after you must have stocked they will start growing and the space will chock them which will lead to most of them dying.
By the time the sack we talked about earlier must have been absorbed in their bodies, you need to start feeding them at least three (3) times daily. The essence is for them to have enough food and nutrient to grow.
Starvation leads to mortality. So, if you still wonder why your catfish fries are dying after meeting other conditions, them is time to revisit how you feed them. Remember, do not overfeed.
6. Pond Size
Does pond size matter in catfish fry management? The answer is a capital YES. This is why it is advisable to make use of a nursery pond when raising your fries. Nursery ponds are usually 3feet in depth which is best for fries. The general idea is not to let the water in the pond exceed above 3feet. At the fry stage, the fish finds it difficult to swim around any depth that is more than 3feet.
Inbreeding as we had explained in the previous posts is the mating of relatives or the mating of fish that are closely related. Hatching male and female fish that are of the same parents is inbreeding. Research has shown that inbreeding affects the immune system functions of the fish, decreases fish growth, reduces fertility, and finally results in mortality. It also increases the right of deformity in the fish.
If you have been experiencing between 40% and above deformity among the fish stocked it could be a sign that something went wrong during the hatching stage. The end result is not far from the fish dying gradually in the pond. Few that may be left will end up having stunted growth.
Summary of How to Prevent Catfish Fry Mortality
- Adequately wash and dry your pond(s) to get rid of any harmful bacteria that might pose a threat to the newly hatched fish.
- Do not feed the fries for the first 24hours after hatchery to avoid overfeeding.
- Monitor their growth to know when to start sorting. This will help to avoid cannibalism.
- Never overstock your pond. When you do they will be chock and start dying.
- Feed appropriately to avoid starving the fries. Starvation causes catfish fry mortality and to prevent this from happening, you must understand how and when to feed them.
- Always make use of the nursery pond while growing your fries. Is smaller and easy to manage.
- The water level in the pond should be maintained at 3feet maximum. Newly hatched fish do not have the capacity to swim below or above 3feet.
- Do not make use of male and female fish that are related during the hatching process as this could lead to the loss of your catfish fries.
There are other reasons why catfish fries die that we are not discussed in this post. Kindly use the comment section or box to tell us the ones you know that you feel should have been included in the post. However, there are benefits of catfish farming, so do not lose your passion due to losses you might have experienced.
Ammonia, nitrite, water quality, and temperature imbalance are other factors that cause catfish fry mortality. The eight (8) suggestions above on how to prevent catfish fry mortality will go a long way in solving the problem of mortality in our various farms.
Do you think that broodstocks immaturity could be a cause? Tell us what you feel.
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