Jumat, 12 April 2013


The seeds are used can be derived from the catchment and seeding. Generally, the number of seeds of catches is very limited, size is not uniform, the disease is often caused by injuries during arrest and transport. For these reasons, better seeds were taken from  seeding. In addition to numerous, relatively uniform size and quality and continuity assured. Healthy seeds look of bright colors, movement agile and active, high appetite and no disability.
In the table below an overview is given dispersive solid standards and measures at all levels of magnification stocking grouper.
Table 1. Standard container maintenance, dense stocking, size TEBA-long maintenance at all levels of magnification tiger grouper (Epinephelus fuscogutattus)
Size of fish (gram)
15 - 25
50 - 75
400 - 500
Container stocking
Stocking pcs/m3
150 - 200
75 - 100
20 - 25
maintenance (month)
Survival Rate of production (%)
> 80
> 85
> 95

Sources: Field set SNI cultivation, Directorate General of Aquaculture, 2002
Optimum densities for nursery phase is 150-200 ekor/m3 with an average length and weight of fish 9-12 cm 15-25 g. Having grown up during the 1 to 1.5 months, the density was reduced to 100 ekor/m3. Density should be maintained until the enlargement 2 months, then the density to 20-25 ekor/m3 maintained for 4 months until the fish reach consumption size (400-500 grams).
Table 2. Standard container maintenance, dense stocking, stocking size, length of culture at all levels of magnification grouper duck (Cromileptes altivelis).
 (Cromileptes altivelis).
Size of fish (gram)
400 - 500
Container stocking
Stocking pcs/m3
breeding (month)
Survival Rate of production (%)
Sources: Field set SNI cultivation, Directorate General of Aquaculture, 2002

The selection of the type of feed for enlargement should be based on the willingness of the fish to eat the food provided, quality, nutrition and price or economic value. In general, for a given grouper fresh trash fish that are relatively inexpensive, can also be made in the form of pellet feed instead of trash fish.
Feeding Frequency

The success of enlargement grouper is highly dependent on the adequacy of the feed. In the early stages of rearing, feeding done as often as possible until the fish is really full, at least three times a day. The next stage of feeding time and frequency should be appropriate to both growth and feed use becomes inefficient, as it relates to digestion and energy consumption. We recommend feeding 2 times a day during the morning and afternoon. Fresh fish food should be chopped to size corresponds to the opening of the mouth of the fish.
Feeding Ratio

The ratio of the feed should be appropriate to the feed given to farmed fish consumed efficiently and provide a better survival, namely:
Table 3. Standard type and dose of feed use at all levels of magnification tiger grouper fish and humpback grouper .
Dose and type of fish feed
Size of fish (gram)
15 - 25
50 - 75
400 - 500
Mean fresh fish (%)
10 - 15
7,5 - 10
5 - 7,5
Pellet (%)
7,5 - 10
5 - 7,5
3 - 5

Sources: Field set SNI cultivation, Directorate General of Aquaculture, 2002
Giving Multivitamin

Uses the addition of multivitamins may increase the immunity of fish that can grow normally, in addition, it can prevent the occurrence of lordosis and scoliosis or curved body for the development of the spine that is not perfect. Another benefit is that it can increase the survival rate of fish, or reduce the mortality rate, affect the performance of the fish, the body color becomes more bright and aggressive. Can also be given additional vitamin C as much as 2 g / kg of feed given 2 times per week.
Table 4. The standard use of the type and dose of anesthetic, desinfectan, and drugs on the enlargement tiger grouper and duck suit 01-6487.4-2000 SNI.
No. Type Dose Specification
1 1 ppm Treflan applied
2 Acriflavin 5-10 ppm Soaking 1-2 hours
3 Prefuran 1 ppm Immersion 30-60 minutes
4 Methilyne blue Soaking 3-5 ppm 30-60 minutes
5 Vitamin C 2-4 g / kg of feed mixing dim feed
6 Multivitamin 3-5 g / kg of feed mixing dim feed
Sources: Field set SNI cultivation, Directorate General of Aquaculture, 2002

To determine the dose of feed necessary to measure the weight and length of fish by sampling (random) by 10% at least once a month. Fish anesthetized before measured. Death during maintenance also calculated to obtain the value of SR (pass on) during maintenance. The growth rate of fish is influenced by the type of feed, the amount and quality of feed given. The growth rate of 1 to 1.3 grams of duck grouper / day, while the rate of growth of tiger grouper from 2.5 to 3 grams / day (the study results Marine culture Center Lampung).
Grouper duck maintained initial weight 1.3 grams and a total length of 4 cm will weigh between 400-500 grams for 12-14 months, while the tiger grouper may be harvested in the seventh with a weight of 525 grams. Weight grouper duck relatively slower than the tiger grouper this is possible because of a genetic indeed slow growth. During observation in BBL Lampung weight duck grouper and tiger grouper for enlargement in floating net is as follows.
Table 5 Added weight Grouper Ducks and Tigers during Phase Enlargement (g)
Tiger Grouper
Grouper Ducks

Sources: Marine Aquaculture Center Lampung, 2001
Spreading Table Solid, Old Maintenance and Production in the Enlarged survival Grouper  Tigers and Ducks.
Fish Species
Grouper Ducks
Grouper Tiger
stocking pcs/m3
breeding (month)
Survival rate (%)
Sources: Field set SNI cultivation, Directorate General of Aquaculture, 2002
Sorting Size
Tiger grouper including wild fish and have a cannibalistic nature. Therefore sorting activities or uniform size should be routinely performed. This is done so that each nets filled only fish of the same size, if there are differences in the size of the smaller fish will not compete with bigger fish to obtain food, it can cause a lot of deaths.
Uniformity of size enlargement is started from the beginning and then forwarded at least once every two weeks, especially if there are variations in size. Sorting is done by mesh size last lifted the fish were taken and placed in a plastic bucket with a capacity of 100 liters, and then selected based on the size of the fish and put back in the container maintenance.

Treatment and control  nets during the enlargement absolutely necessary. nets that can inhibit the exchange of dirty water and oxygen and inhibit growth and cause disease in pet fish. Replacement  nets with a net gross performed at least 3 weeks.dirty nets to dry and then washed with water spraying. After returning to dry clean dried, before being used nets controlled again if there is a damaged or broken.

Fish health surveillance should be carried out to observe the visual and organoleptic and morphological fish ectoparasites. While the observations made in the laboratory for microscopic examination of the bodies of the pathogen (endo perasit, fungi, bacteria and viruses).
How to measure water quality (temperature, salinity, pH, dissolved oxygen, ammonia, ammonium sulfate, nitrite, nitrate, chlorine, etc.) is done by using a thermometer for temperature, refractometer to measure the salinity, pH meter or litmus paper to measure pH, DO meter to measure dissolved oxygen and water quality test kit to measure water quality more adapted to guide the work of each of the tools used. Frequency measurements were made at least twice a week.
Sources: Technical Manual Marine culture
Groupers, DG P. Cultivation

Jumat, 01 Februari 2013

Red snapper (Lutjanus argentimaculatus)

Red snapper (Lutjanus argentimaculatus)

Classification of Fish Red Snapper (Lutjanus argentimaculatus)
According Saanin (1984) classification of red snapper are as follows:
Kingdom: Animalia
Phylum: Chordata
Sub-phylum: Vertebrata
Class: Pisces
Sub Class: Teleostei
Order: Percomorphi
Sub Order: Perciodea
Family: Lutjanidae
Genus: Lutjanus
Species: Lutjanus argentimaculatus

Morphology and Anatomy Fish Red Snapper (Lutjanus argntimaculatus)
Red snapper (Lutjanus argntimaculatus) which has an elongated body and a wide, flat or oval, convex or slightly concave head. This type of fish is generally wide mouthed and sunken face, teeth konikel the fangs are arranged in one or two lines with a series of teeth caninnya located at the front.
The lower part of the gill cover pre-shaped serrated ridge with a sharp tip. dorsal-fingered hard 11 and weak 14, anal fin of radius 3 weakly hard 8-9. Generally continuous dorsal fin and grooved on the section between the hard and thorny spiny soft parts. Tail slightly concave rear boundary with both ends slightly blunted.
Color varies greatly, ranging from reddish, yellowish, gray to brown. Anyone have dark stripes and sometimes encountered any black spots on the upper side of the body just below the dorsal fin beginning fingers software. In general, a length of between 25-50 cm, although it is not uncommon to reach 90 cm (Gunarso, 1995). Red snapper receive various information about his surroundings through multiple senses, such as through the senses of vision, hearing, smell, touch, line laterals and so on.
Red snapper fish is classified diecious separate between males and females. Almost no sexual dimorphism or found significant difference between male and female types both in terms of structure and in terms of color. Gonokorisme reproductive pattern, ie after the differentiation of sex, the kind of sex would take place during his lifetime, male as male and female as females. This type of fish attained an average body length at first maturation has reached 41-51% of the total body length or maximum body length. Males having sex mature at a smaller size than females. Groups of fish were ready to spawn, usually consisting of ten tail or so, will come to the surface at dusk or at night in the month of August with the water temperature ranges between 22.2 to 25.2 º C. Males who took the snapper spawning ongoing initiative that begins with touch and rub their bodies on either a female. After that other fish join, they spin off of gametes to form a spiral while slightly below the water surface.
In general, red snapper that size would also increase the maximum age than small ones. Red snapper that are large will be able to reach the maximum age between 15-20 years old, mostly inhabit waters from shallow to a depth of 60-100 meters (Gunarso, 1995)

Distribution Fish Red Snapper (Lutjanus argntimaculatus)
Red snapper (Lutjanus argentimaculatus) mostly inhabit the waters of the reef area to the tidal estuary, and even some species tend to penetrate down to freshwater. Type of large red snapper are generally formed gangs that are not so great and stocks to occupy the bottom waters deeper than smaller species.
Also usually red snapper caught at depths between 40-50 meters with the base substrate few corals and 30-33 ppt salinity and temperature between 5-32 º C (Center for Fisheries Research and Development, 1991). Types of small-sized aggregate is often found near the surface waters of the reef during the day. At night is generally spread in search of food in the form of fish and crustaceans. The fish are small for some types of snapper usually occupy shallow mangrove areas or areas that are overgrown with seaweed. Family Lutjanidae mainly inhabit tropical and sub-tropical waters, although three of the genus Lutjanus there that live in fresh water (Baskoro et al. 2004).
The spread of red snapper in Indonesia is very broad and almost inhabit the waters of the coast of Indonesia. Spread red snapper direction to the north reaches the Bay of Bengal, Gulf of Siam, along the coast of the South China Sea and the Philippines. The spread to the south towards achieving the tropical waters of Australia, direction west as South Africa and the tropical waters of the Atlantic United States, while the eastern direction to reach the islands of the Pacific Ocean (Directorate General of Fisheries, 1983 in Baskoro et al. 2004).
According Djamal and Marzuki (1992), the ranges of red snapper in almost all waters of the Java Sea, ranging from Bawean waters, islands Karimun Jawa, Sunda Strait, Java, South, East and West Kalimantan, Sulawesi waters, Riau Islands.
Economical and Ecological Value of Fish Red Snapper ((Lutjanus argntimaculatus)
Red snapper or red snapper is one of economically important fish species. Red snapper has a large market share, but its production is small so its use should be enhanced to support the export as well as local needs. But, the potential for red snapper are rarely found in large gangs and tend to live solitary with a diverse environment ranging from shallow waters, estuaries, mangroves, coastal areas until local or craggy rocks. Besides the red snapper can also be eaten as meat thick, white, tender and juicy. A good size for consumption should be a medium-sized still, because of the large size most at risk of heavy metal-containing high levels of mercury.
The red snapper commonly inhabits waters of the reef area to the tidal estuary, and even some species tend to be through to the fresh water. Type of large red snapper are generally formed gangs that are not so great and stocks to occupy the bottom waters deeper than smaller species. Also usually red snapper caught at depths between 40-50 meters with the base substrate few corals and 30-33 ppt salinity and temperature between 5-32 º C (Center for Fisheries Research and Development, 1991). Types of small-sized aggregate is often found near the surface waters of the reef during the day. At night is generally spread in search of food in the form of fish and crustaceans. The fish are small for some types of snapper usually occupy shallow mangrove areas or areas that are overgrown with seaweed. Potential red snapper are rarely found in large gangs and tend to live solitary with a diverse environment ranging from shallow waters, estuaries, forests
mangroves, coastal areas until local or craggy rocks. Family Lutjanidae mainly inhabit tropical and sub-tropical waters, although three of the genus Lutjanus there that live in fresh water (Baskoro et al. 2004).

Breeding Barramundi (Lates calcariver) HOUSEHOLD SCALE (Scale Hatchery Household)

Breeding Barramundi
(Lates calcariver) 
(Scale Hatchery Household) 

Barramundi (Lates calcarifer, Bloch) is a type of fish have a high economic value, both to meet the consumption needs domestically and abroad. At first barramundi production obtained from the by-product of farming in ponds, but now the fish This is specially cultivated in floating cages in the sea. Today in and surrounding Bengkalis (Riau Islands) has been developed with extensive potential area of ​​340 hectares. 
The main problem in the cultivation is limited available seed both in quantity and quality constantly and continuously. 
As an illustration, in estuaries Batam (Bengkalis - Kep. Riau) there floating cages as much as 550 units, each unit spread 1,000 animals seed size so it takes 550,000 spindles fry size 
logs or 2.75 million fry age D30. By hanging seeds from the wild, of course not sufficient due to the number obtained very limited, low-level uniformity and continuity is not assured. 
Large-scale barramundi hatchery managed by the private sector to date does not exist, therefore the barramundi hatchery household scale (Hatchery-Scale Household) needs to be developed because it has prospect. 
In principle Hatchery-Scale Household shrimp can be developed into Hatchery-Scale Household   barramundi considering the facilities and infrastructure required for seeding snapper not much different from the white shrimp hatchery. Thus when done for the development and diversification of business continuity aquaculture commodities in question as well as to provide flexibility trying so capital has grown to continue to operate. 

Criteria Hatchery-Scale Household barramundi are: 
1) As a side job for the family by utilizing the house as 
business location and family members as the workers.  
2) The equipment used reflects the simplicity that 
give the impression of easy to follow in terms of both investment and 
3) If the operation is done in such a way that the use of 
sea ​​water pump to a minimum, so as to conserve 
electricity which in turn can reduce the cost of production. 
4) Carry out business activities are limited, example larval rearing 
from egg to D20 s / d D25 or D20/D25 D1/D2 up. 
5) Implement the investment is relatively small so it is easy to follow by the community 
6) With the simplicity of the ingredients, some production inputs such as egg 
barramundi, algae (phytoplankton) and ritefer (zooplankton) depends on 
Another seeding. 
7) Number of units like larva per family is preferred, 
than or equal to three. Due to the large amount of air 
more and more fragmented, the concentration should be more complete means 
needed. Tub size adjusted to the capabilities and extensive 
land, suggested measures like a minimum of 10 m3. 

Barramundi hatchery effort household scale is expected to 
benefits include: 
1) Help solve the difficulties farmers are always floating brackets 
shortage of seeds at planting time. 
2) Provide a perch with a lower price with quality 
good thus increasing the competitiveness of Indonesia's barramundi 
international market. 
3) Make use of garden soil and increase families revenue,especially those located in coastal areas. 
4) Create jobs. 
5) Support the national program "Increase Non-Oil Exports" through 
procurement of one component in a system of aquaculture production snapper 
6) Assist the provision of seeds to farmers in brackets floating fish 
provide opportunities and educate them to produce seeds 

Success in barramundi hatchery operations depends 
in the right location, the things that need to be considered in the site selection are as follows: 
1) Sea Water Sources 
Source of sea water used for seeding should be clean and clear all year, relatively small changes in salinity. Appropriate location usually in the sheltered bays of the waves / strong currents and is located in the rocky and sandy beaches. What also should be away from agricultural and industrial waste disposal. Technical requirements and physical chemistry qualified are as follows: 
- Salinity: 28-35 
- PH: 7.8 to 8.3 
- Alkalinity: 33 - 60 ppm 
- Organic matter: <10 ppm 
- Ammonia: <2 ppm 
- Nitrite: <1 ppm 
- Temperature: 30-33 degrees Celsius 
- Clarity: maximum 
2) Ease 
What should be located at a distance of less than 3 hours drive from the location 
mother cooked eggs, 12 hours from the supplier locations eggs / larvae D1 and no more than 12 hours of travel to marketing. 
3) Sources of Fresh Water 
Fresh water is needed to reduce the salinity of sea water is needed as needed. Besides fresh water is also used for wash tubs and other seeding equipment that are not easily corroded. 
4) Power Source 
Seeding can not be operated without electricity. Electricity is essential as a source of power to run appliances such as seeding blower, water pump and other supporting systems. Installation of generator absolutely necessary especially for the frequent outages occurred electricity. 
5) Topography 
Location seeding must be located on flood-free areas, waves and tide. What should also consist of land solid / compact. Although household-scale hatchery small overall, but like larva fixed tonnage large that the land base that is stable enough to be selected, for example former landfill waste in order to avoid water power is assured. 

1) Facility 
Facilities required in barramundi hatchery small scale quite simple: pump, water tank fresh and sea water,water natural feed, bath tub, larval rearing and hatching artemia, aerator / blower and equipment as well as field equipment supporting. 
a. Pump 
Pump is needed to get sea water and fresh water. When relatively clean sea water can be pumped directly into the air filter and stored in the water tank. 
If sea water is relatively turbid and contains a lot of mud particles,the sea water in the sedimentation basin, then the surface is relatively clear water in the pump to the strained tub, 
pump specification should be chosen well as the size of the pump depending on the amount of water required per time unit, it is recommended for Hatchery-Scale Household with a capacity of 3 tubs each larval rearing with a capacity of 10 m3 of water, pump size 1.5 inches. 
b. Freshwater and Seawater reservoirs 
Water reservoirs built at a height such that so that the water can be distributed by gravity into a bath-tub and other facilities requiring water (sea, fresh clean). The basin made of cement and air volume should be at least equal to the volume of water larval rearing. If there is no special tanks can using larval rearing tubs are used as water reservoirs, and then flowed to the pump submarsibel
c. Tubs Maintenance of larvae 
larva basin can be made of cement, glass fiber or plastic coated wood construction, each ingredient has advantages and disadvantages. Tub size can be made according to the capacity and production targets to be achieved, but it is suggested capacity / volume of at least 10 m3 due to the volume of water that smaller temperature stability is less assured.Water high between 1.2 to 1.5 m,tubs that are too high will complicate the management of day-to-day. 
Shapes like round or square can. Depending on the amount of funds and tastes. That must be considered in terms of the shape and size of the tub is not complicate the management of day-to-day also eases water circulation. Tub with a spherical shape, the discharge channel located 
in the middle of the base slant (slope 5%) to the middle (to channel disposal). In the sewer pipe can be fitted upright to regulate and control the water level. The tubs preferably elongated rectangular for ease change the water and the corners should not have corners die (sharp corners). Sharp corners will cause water circulation not perfect so the rest of metabolites and other impurities accumulate on corner bath, in addition to the sharp corners will also be difficult in cleaning the tub. On the air in a rectangular duct intake and discharge of water placed on the opposite side, can be mounted on the drain standpipe (pipes shake) to regulate and control the water level. Basic tub made crooked by slope of 5% in order to facilitate the cleaning bath. Moreover walls and bottom should be smooth like that are not easily attached dirt, fungi and parasites as well as not to complicate the cleaning bath.For the purpose of harvesting the seed, either in the tub or round shape a rectangular shape on the end of the discharge line is equipped with a small tub for collect seeds to be harvested. 
Larval rearing tubs require a cover over it to prevent entry of dirt and foreign objects are not desired and maintenance to protect tub from rain. Close tub can be made of plastic and should be dark to protect water / media larval rearing of excessive sun exposure, so prevent the blooming of plankton in the water medium maintenance larvae. Furthermore tub cover can also prevent the occurrence of fluctuations temperature is too high and can raise the temperature in the tub larval rearing. 
d. Tubs Plankton Culture 
Plankton (phytoplankton and zooplankton) is absolutely necessary as food for larval rearing barramundi is when the larvae begin take / need food from the environment as a backup food in the form of egg yolk has been exhausted. In addition to the natural food, phytoplankton also serves as a water quality control and the culture of food for zooplankton / rotifer. 
The tub to culture plankton can be made with wood construction plastic coated, due to the volume required is not too great. Tub size is 2 x 2 x 0.6 meters each 4 pieces for culture phytoplankton and 4 again for the culture of zooplankton (each tub plankton culture replete reserves). The number and size of the tub culture plankton was sufficient to provide a natural food cycles maintenance (3 larva tub with a capacity of 10 m3). 
e. Tubs Artemia Hatching 
Other natural foods that are needed for life Artemia larvae salina. Artemia on the market or the public is a form of cyste eggs, so that to obtain naupli artemia are ready to be given to the 
have hatched larvae as food first. For obtain naupli, cyste can immediately hatched before hatching. Artemia hatching tub can be made of fiber glass or plastic conical cone fitted on the end stop Faucets for naupli harvesting artemia. A cone shape the best alternative because it is only with one aeration stone at the base of the cone can stir all the water in the tub evenly hatching, so that the hatch can cyste well because no one sediment or attached at the bottom of the tub. Volume hatching tubs should a minimum of 25-30 liters for the hatch artemia cyste much as 150-200 grams. 
f. Aerator 
Larvae require dissolved oxygen in the water for metabolic processes in the body, other than that produced by an water bubble aerator can accelerate the evaporation of a variety of toxic gases larval rearing water medium. In addition to price considerations, aerator better shape and small size, the pressure force is large enough (To a depth of 1 to 1.2 m) and small power requirements. Another device of aerator is stone aeration, aeration tubing and aeration regulator to regulate water pressure. 
2) Field Equipment 
To support the management of day-to-day hatchery needed some plastic buckets, among others, to hold food before it is given to larvae, harvesting buckets to collect and count the seeds and buckets to filter water when its cleaned. Other equipment is scoop to sow feed, blender for mixing and smooth feed made when necessary, filter feed (plankton net) in various sizes to suit with wide mouth opening larvae and water hoses of various sizes to suit needs. 
3) Design of Hatchery Scale Household 
The layout Hatchery Scale Household all facilities should be arranged in such a way as mature and show proper dimensions so that land and facilities available can be used as efficiently as possible, which in turn can facilitate the daily work and reduce operating costs. 

1) Maintenance of larvae 
Before the larvae moved (approximately 1-2 days in advance), water larval rearing should be washed with fresh water and then dry brushed for 1-2 days. Cleaning the tub can also be done by dissolving hypokhlorine 150 ppm sodium solution on the walls of the tub, then dried for 2-3 hours to remove chlorine are toxic. Water larval rearing media were free of contamination with temperatures 26-28 degrees Celsius and salinity 29-32 ppt into a tub filled with filtered manner with a sand filter or filter fabric to avoid dirt carried by sea water. To supply oxygen aeration system and the bath has aeration stones are placed evenly dispersed so that the overall water in the tub. The newly hatched larvae have a total length of 1.21 to 1.65 mm, floated on the surface of the water and close group aeration. Age 30 days larvae were placed in the vessel sheltered from the direct influence of light sun (semi out door tanks). 
Solid start stocking the tub maintenance is 70-80 larvae / liter volume of water. On days 8-15 the density was reduced to 30-40 larvae / liter, after day 16 larval density was lowered to 20-30 
larvae / liter, because at this age the larvae has shown differences in size and the nature of cannibalism. 
2) Natural Feeding 
Since the first larvae had to be given Chlorella and Tetraselmis, besides as the larvae feed, also function as a water quality control and feed rotifers. Solid stocking for Tetraselmis is 8-10 x 1000 cells / ml, while for Chlorella is 3-4 x 10,000 cells / ml. Age 2 days, the larvae have started to open his mouth, this time to day 7 into the tub added Rotifers (Brachionus plicatilis) with solid stocking 5-7 individuals / ml. On day 8 to day 14 giving Rotifers increased the number to 8-15 individuals / ml. At the age of 15 days were fed Artemia larvae begin with density 11-2 
individuals / ml. After the age of 30 days, with a body length of 12-15 mm larvae already can eat chopped fresh meat. 
3) Water Management 
Good water management can provide rapid larval growth the level life (survival rate) is higher. In this case the most important is to always maintain an optimal environment for growth and larval life. Besides changes emergent or environment will not support resulted in the death of larvae, as well as to reduce the mortality rate to consider the problem of sanitation and feed settings are carefully .Noteworthy good water management. In the larval rearing water barramundi replacement is started at 13 days to as much as 10-20% a day until day 14. At day 15 until day 25 the replacement of water by 30-40% done
7. Classification SIZE (Grading) 
Larval rearing barramundi in a limited primarily to competition feed and the room will result in uneven growth. Size classification (grading) is intended to prevent mutual ate fellow larvae (cannibalism), because perch have the property carnivor (predator fish). The nature of cannibals on larval perch will be more visible when started eating artemia (± 10 days). 
Containers used for the classification of plastic the size of the hollowed walls of certain sizes, the size of the hole  between 2.5 - 10 mm. Size classification is done by inserting a plastic basin to the maintenance on the aeration basin, the fish are smaller than hole can escape and the larger larvae can not escape, then if larger larvae were separated and size by using a bowl that has a hole the size of more large. This method will separate the fish into some specific size and simplify management. Classification done twice the size of the first grading day to 10-14 and classification both at day 20-25. The size of the hole between 2.5 - 10 mm. 
How to harvest depends on the shape and capacity of the maintenance for the bath has a line out would be more easily done by placing the current water out. While that is no outlet, harvesting is done by how to reduce the water in the tub to a depth maintenance living 10-20 
cm, then the seed was arrested by scoopnet. In order for barramundi larvae do not undergo stress at harvest, done carefully and in shelters are given sufficient aeration.