3.11 , 3.12 Probiotics: The "bio" of a Biofloc system

The "bio" in Biofloc

At its core, biofloc is a waste treatment system. Biofloc systems use a counter-intuitive approach and allow or encourage solids and the microbial colonies to accumulate in water. Water quality can be controlled as long as there is sufficient mixing and aeration to maintain an active floc in suspension. For more information about the principle of biofloc technology, click 👉 here.

What is Probiotics?

Probiotics are usually live microorganisms which when administered in adequate amounts confer a health benefits on host. Nowadays, probiotics are also becoming an integral part of the aquaculture practices to obtain high production. The common probiotics that are used for aquaculture practices include Lactobacillus, Lactococcus, Leuconostoc, Enterococcus, Carnobacterium, Bacillus, Aeromonas, Enterobacter, Pseudomonas, Clostridium, and other genera. 

The involvement of probiotics in nutrition, disease resistance and other beneficial activities in fish has proven beyond any doubt. The most common use of bacterial colonies can be described in a broad sense as the conversion of all kind of wastes in a fish tank to a secondary protein rich food source for the fishes. It is an innovative and cost-effective technology in which toxic materials to the fishes such as leftover food, organic wastes, excreta of the fishes, dead fishes, etc. can be converted to useful product, i.e., proteinaceous feed. This feat is achieved by the bacterial colonies that are manually administered for this specific purpose. 

When we discuss water preparation later, we will discuss about the bacterial colonies and their benefits in a biofloc system in depth.

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5. Difficulties faced by beginners

When we started this business, we couldn't gather the proper information about biofloc fish farming. Although we had completed our costly one day training from a "self-proclaimed" know-it-all trainer, we were still in the dark about a lot of stuff related to this aquaculture technique. So, naturally we faced a cluster of problems which seemed insignificant to us because of our lack of knowledge.

Yeah. We failed to plan properly. 😔

 

That made us realize that most of these problems are not addressed by the novice trainers during the short training span and most beginners will face several of those problems. In this post we are going to try to address as many problems we can, so that beginner agriculturists do not have to face the problems we did.

Problems faced in the early stages :

• Maintenance of the floc
• Mortality of fish seeds during transportation 
• Sanitization of fish seeds before releasing them to the tank
• Ammonia spike in the first few days
• Formation of foam on the water surface
• Problems due to sudden temperature drop

We'll try to briefly explain them. 

Maintenance of floc :

Source: LINK

When we are preparing the water in the tank before the arrival of the fishes, we add a required amount of probiotics powder with a carbohydrate source, like molasses and keep the tank running for about 3 days before we add the fish seeds. The formation of the floc happens during these few days. So we should keep the aeration on so that there is vigorous water movement because the floc needs to be in suspended state in the water. The dissolved oxygen (DO) must be checked because the bacteria need oxygen for their survival. Temperature of the water should be maintained above 20℃. A rule of thumb is to release the fishes within 60-72 hours from the time of inoculation (addition of the probiotics) otherwise add some fish food so that the bacterial colonies survive.

Mortality because of transportation :

Fish seeds oxygen packed in poly-bags for transportation

When we go to buy fish seeds (juvenile fishes which we are going to rear) from breeders, we either get them delivered to us by transportation or we can carry them personally. Every time we got new fishes delivered to us or even if when we went to buy them ourselves, there were a lot of casualties. We were actually panicking because we thought that we must be doing something wrong which was causing the fish moralities. Now we know that some fishes will die during transportation. This is mainly caused by stress in the fishes because of the whole ordeal and also because of lack of DO in those packed plastic bags. We have noticed the mortality rate is somewhere between 2-5% in most cases.

Sanitization of fish seeds before releasing them to the tank :

In the first few cultures, we used to bring the fish seeds and then happily release them to the tank. Hardly did we know what mistake we were making. Actually the thing is that these juvenile fishes usually carry a plethora of pathogens and parasites. So, it is very very important to sanitize them first before releasing them to the tank. 

I use a solution of 1 gram of Potassium permanganate powder in 20 litres of water to sterilize the fish seed before releasing them in the tank. This helps in getting rid of the unwanted pathogens that the fishes carry with them. I do it by taking the fishes in a net and dipping them in the solution for about 10-15 seconds, and then dipping them in clean water and then releasing them. I have noticed that this process helps in getting rid of  many extremely lethal parasites like Ich.

Ammonia spike in the first few days :

Level of ammonia is 8 ppm

Biofloc technology is a high density fish farming technique, we can say that we intentionally overstock the tank critically. After the release of the fish seeds, the fishes are under stress caused by numerous reasons. Hence they do not consume food in the first few days or consume food less than usual. This leftover food and sunken dead fishes causes a massive increase in the ammonia levels in the tank because the floc is not yet that active or maybe because of less than adequate floc in the water.

A simple but temporary solution to cope with the ammonia spike is to add carbon source like molasses or sugar in a controlled way. This is not a permanent fix, just a temporary solution.   

Formation of foam on the water surface :

Source: Facebook

You can see thick white foam in some biofloc tanks. This may look alarming but it is actually not that big of a deal. This foam is caused when we add more probiotics weekly for the maintenance routine. A proper aeration will help you a bit. Instead of adding the probiotics weekly, you can try setting up a FCO tank. This eliminates the foam on the water surface.

Problems due to sudden temperature drop :

Too cold? 

Fishes are cold blooded creatures i.e they regulate their body temperature with respect to the temperature of the water they're swimming. Hence fishes find it difficult when there is a sudden change in temperature. If the temperature is below 20 degrees they will get lethargic and stop accepting food and die eventually. To know more click 👉 here.

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3.10 Importance of water temperature in aquaculture

Biofloc is one of the most innovative techniques in aquaculture which results in better production of fishes, invertebrates in manually controlled tanks. Since, it is a comparatively new technique of fish farming, clouds of confusion form in everyone's minds. Fish farmers are being confused by YouTubers and "fake Biofloc trainers"  and misguided into believing totally made-up information. That is why we chose to address each and every parameters and write about them in separate posts. That brings us to another very important, but totally ignored parameter, i.e. water temperature.

Water temperature

Since we are based in West Bengal, India, which is moderately warm and humid for almost 8 months, we asked our trainer whether the warm atmospheric temperature would cause problems for us. He very casually told us that this biofloc technology works better in warmer regions, and we can attest that this is a wrong information. Temperature plays a very crucial role in a biofloc systems. 

 A biofloc system works perfectly when all the parameters like pH, TDS, temperature, DO, dissolved Ammonia work hand-in-hand in total harmony. A slight change can wreck havoc if left unnoticed. From our experience, with respect to the environmental conditions in our region, the optimum temperature is 25℃-28℃, although we haven't faced any problems till 30℃, but it not advisable. 

Optimum temperature: 25℃ - 28℃

Effects of temperature in biofloc tank

We will discuss some ill-effects of rise and fall of water temperature from the optimum range and how it affects the livestock. 

• If the temperature increases during summer above the optimum mark, the DO (dissolved oxygen) level fall drastically, and the carbon dioxide levels increase. If you're cultivating fishes that respire using the dissolved oxygen, they'll come to the surface of the water and start gasping for air. If the DO level are not increased promptly, fishes will start dying and you'll end up with a huge number of dead fishes on your end.

  

  Carp babies gasping for air because of low levels of dissolved oxygen

  
  
• If the temperature increases above the mark, then deflocculation of flocculants happen, which means the floc doesn't remain in suspended stage in the water, and they fall down at the form and form sludge, causing a sudden spike in Ammonia level causing death of fishes. 
• Deflocculation of floc also happens when the temperature drops too low at around 8℃ or lower. The outcome is the same as the previous point, Ammonia level increase, causing massive death of the livestock.
• Increase and decrease of temperature causes sudden increase in the nitrite levels in the fish tank too, if the TDS of the water is not up to the desired mark, fishes will perish.

  

  Dead catfishes floating due to nitrite poisoning

• Fishes are cold-blooded creatures, i.e. they regulate their body temperature with respect to the temperature in the water they're swimming. Hence, fishes feel stress when the temperature changes, which will be reflected in their behaviour. If the temperature is lower than 20℃, they will get lethargic, stop accepting food and they will die, eventually. 

TIP

No matter wherever you're from, try hard to maintain the temperature of your fish tanks, fishes will be stress free and you will be blessed with a great harvest every single time. 

Optimum temperature: 25℃ - 28℃

Recommended 

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Venus Aqua Aqua One Electronic Thermometer for Fish Tank

Piper Digital Water Thermometer for Fish Tank

R-tek Digital Thermometer with LCD with Wired Probe

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3.8 , 3.9 Why is salt used in aquaculture?

Raw salt and Biofloc fish farming: a weird relation

You may have read posts somewhere on the internet or watched videos on YouTube about Biofloc fish farming, and you may have wondered why is salt, specifically raw salt, used for freshwater fishes. Right? I mean, we're mainly cultivating freshwater fishes or crustaceans and not marine fishes, so why add salt in the water? When I was starting this business, this was one of the first questions to pop up in my head and I had to find the reason behind this. I will try my best to explain why is salt used and why is it one of the most important parameters in Biofloc fish farming.

Understanding TDS

TDS stand for Total dissolved solids. TDS is a measure of all the dissolved inorganic and organic substances present in a liquid in molecular, ionized, suspended form. TDS of any liquid (here water) is measured as parts per million (ppm).

Why is salt needed in a freshwater fish tank?

Raw salt and not the ordinary processed salt is used in aquaculture. Raw salt is the salt extracted from sea water, unprocessed and without any added chemicals like Iodine. Hence, raw salt is totally unprocessed and free of chemicals like Iodine which is beneficial to us, but harmful to the bacterial floc in the biofloc fish tank.

Benefits of using raw salt in aquaculture : 

Addition of raw salt when monitored carefully has a plethora of benefits. I cannot list all of them, but I'll try: 

1. Biofloc is a high density fish farming, and fishes develop stress when they're overstocked. Stress is accompanied by the release of the hormone cortisol, which is responsible for having a negative effect on growth, reproduction, and digestion. Chronic stress will also lower the ability of the immune system to respond effectively which allows parasites, bacteria, and fungi to infect a stressed fish, causing disease and death. Salt acts as a very good stress reliever of fishes. 
2. Clean freshwater if stored for a few weeks in a clean container deteriorates in quality. It may be because of bacterial or algal growth or leaching of chemicals from the container that causes the previously clean water to "go bad". Salt acts as a preservative of water.   
3. Salt effectively controls some parasites of fishes. Salt protects the freshwater fishes from entry of certain pathogens like fish lice, anchor worm, etc.
4. The bacteria in a biofloc fish tank is bound together by a loose matrix of mucus.  Salt helps in the formation of floc, acting as a flocculating agent. 
5. Salt helps in the secretion of mucus of fishes. Mucus protects a thin protective layer over the fishes' body, protecting it from entry of parasites and diseases.
6. Increased chloride concentration in water through salt application is an effective way to prevent nitrite toxicity. Common salt is 60 percent chloride, and chloride ions bind to nitrite cell receptors on the gills, preventing nitrite ions from being absorbed by the fish. Therefore, salt helps protecting fishes from Nitrite poisoning. 

TIPS: 

➢TDS of your tank can easily be measured by using a TDS meter. In a biofloc tank, there is no need for costly salinity meters or refractometers. A simple TDS meter will do the job easily. 

➢There's no need for your TDS to be 1800 ppm or more or less. You first need to check the TDS of the water in your locality. Then you have to keep on adding raw salt until the TDS increases by 800-900 ppm. 

Let's say, the TDS of the water in your locality is 600, then your resulting TDS has to be between 1400-1500 ppm.

Similarly, if the TDS in your locality is 300, then your resulting TDS have to be between 1100-1200 ppm.

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3.3, 3.4, 3.5 Air Pump Accessories

What are the accessories for air pump? 

Just an air pump won't be of any use to you. For that you'll need other attachments like air pipes, air stones, controllers, non-return check valves,etc. We will be talking about them in my own words, hopefully you'll find it useful.

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• Air pipes

The only duty of an air pump is to pump air from the atmosphere through its nozzle, air pipes are then used to "transport" the air from the aforementioned nozzle to the tank. That air is then released underwater through air stones, but that's another story we'll talk about later.

The pipes used for aeration in fish tanks usually have an inner diameter of 4 mm (0.16 inch) and are made of plastic,silicone, etc. Both have their own pros and cons. Plastic pipes are cheaper but they become hard and loose their flexibility and gets damaged because of kinking. Silicone pipes are comparatively a bit costlier, but they are soft, flexible and they resist wear and tear way better than plastic pipes.

I've noticed that using silicone pipes are better because the ends don't get loose after repeated insertion of the nozzle of the air stones or air controllers, and that is very helpful because a loose end will cause the nozzle of the air stone to slip out and trust me, it is very very hard to find the fallen air stone in a tank full of water with fishes and floc in it. So, if you take my advice, go with silicone pipes, you will not regret. Maybe it will cost you a little extra but will save you from all the troubles we had to go through because of our bad decisions. 

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• Air stones

Air stones, also called "air-bubblers" are important fish tank accessories. Their nozzles slide into the cavity of the air pipes and the air from the pump is released through their pores in the form of bubbles. Air stones do not directly mix oxygen into the water. What they do is cause agitation on the surface of the water, allowing greater volume of water to release the built-up carbon dioxide and take in more oxygen.

There is a myriad collection of air stones in the market today. Try to go for cylindrical air stones with brass nozzles. The brass nozzle is longer lasting and has ridges that prevents them from slipping out.

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• Controllers & connectors

Controllers are plastic attachments used to control the volume of air passing through the specific pipe. We should always opt for the sturdier controllers that are available, although a bit costlier. 

Connectors are plastic ornaments too with a specific purpose, to divide one air line to two or three secondary lines. I always buy about a dozen extra because I do not know how I always keep losing them. 

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3.1 Use of Potassium Permanganate in Biofloc Farming

• Potassium Permanganate

Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline solid, that dissolves in water to give intensely pink or purple solutions. In a layman's term, it is a moderately strong  "chemical" that will react with any organic matter in a biofloc fish tank, and oxidize them. Therefore it is used extensively by fish farmers to disinfect their ponds or fish tanks to get rid of any microbial lifeforms like algae, bacteria and kill them and purify their ponds or tanks. 

It is available in pharmaceutical stores in small sachets and packets of around 50 grams, and it can be cheap or a just a little bit costly depending on the locality. You can find it in crystal forms or powdered form and the colour varies from very dark pink to purple which become deep purple when dissolved in water. 

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• How to use it :

1. Buy a small pack of Potassium permanganate from any pharmaceutical shop, you can buy as much as you want but you won't need a lot of it, so you can store it for future use. I use the product shown below. 
   
2. Open the pack, you'll find a purple or dark pink coloured powder. Take just a small amount of it, about 3-4 grams. 
   
3. Dissolve the powder in a bucket full of water, it will easily dissolve in water resulting in a purplish solution.
4. Spray or pour the solution all over the walls carefully.
   
5. Wait for a about 30 minutes and wash it off thoroughly with clean water. Let the water drain out totally.
   
6. Fill it with clean water up to the desired mark and proceed with the next step. 
   

• Other uses of Potassium permanganate :

I use a solution of 1 gram of Potassium permanganate powder in 20 litres of water to sterilize the fish seed before releasing them in the tank. This helps in getting rid of the unwanted pathogens that the fishes carry with them. I do it by taking the fishes in a net and dipping them in the solution for about 10-15 seconds, and then dipping them in clean water and then releasing them. I have noticed that this process helps in getting rid of  many extremely lethal parasites like Ich.

• Tips :

• Potassium permanganate stains skin and clothing and should be handled with care. Clothing stains may be washed away using acetic acid (vinegar). Skin stains usually disappear within 48 hours.
• Potassium permanganate rapidly loses its potency when exposed to light and air. So keep any solution you make up well away from light and in a airtight container.
• Ensure you clearly mark any such container as POISON and keep it well away from children. 
• Wear rubber gloves and use masks when handling Potassium permanganate. 

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