Albino Marble Goby

Brown blood disease

Nitrite (NO2-) is toxic for fish when it is absorbed by fish and reacts with hemoglobin to form methemoglobin (Met-Hb). In this reaction, the iron in the “hem” of hemoglobin is oxidized from ferrous to ferric state, so it can not combine with oxygen to bring this compound to the essential organs of the fish. For that reason, reducing activity of hemoglobin or anemia iscalled nitrite toxicity or metheglobinemia. The blood of fish that contains significant amounts of methehemoglobin is brown in colour, so the common term for this poison is “brown blood disease”

Sleepy Cod

One of the most promising fish for future aquaculture. This fish has many qualities to give it all-round appeal as aquaculture species for the future.

• It has been argued that this species has the best eating quality of all Australian freshwater fish.
• Extremely easy to transport at high densities.
• High flesh recovery.
• Can be kept and grown in high densities.
• Never have muddy flavour.
• Early indications are that it will be unsuitable for pond grow-out situations, however will probably be ideal for growing in recirculating systems.

There are a few smaller growers who have already tried these fish for themselves with positive result. These growers have not had the benefit of having a blue print to follow.
In Asia there already exists a fish very similar to our Sleepy Cod. It is known as the marbled or sand goby (Oxyeleotris marmoratus). Asian sleepy cod are grown throughout South East Asia, particularly in Malaysia, Thailand and Vietnam. They are the highest priced freshwater fish in Asia, with farm gate prices of over AU$30 in Taiwan. Retail prices in Malaysia and Thailand are around AU$45 per kg. This fish fetches some of the highest prices, (around four times that of Silver perch) and is regarded as top quality. There is no doubt an overseas market is out there just waiting for someone to meet.

Shipping live, market sized Sleepy Cod, should prove to be relatively unchallenging. They do seem to live up to their name, “sleepy” and lay motionless in shipping bags. This means their use of oxygen is minimal and therefore production of CO2 low. Many large fish should be able to be packed in an absolute minimum amount of water.
Experienced hatcheries have no difficulty producing fingerlings, however they are one of the more time consuming species to produce, with a low larval to fingerling survival rate, and therefore are an expensive fingerling. If you intend to purchase fingerlings they should be ordered well before the season begins to avoid disappointment.
The picture at the top of the page is of a wild caught orange fish. This orange form is extremely rare in nature. Research conducted by the Walkamin Research Facility in Far North Queensland has so far not been able to reproduce this colour in commercial quantities. All off spring are brown until they reach approximately 120-150 mm. About 5% of offspring have orange blotches, mostly about the head. Only 2-3% attains full colour. This research has been suspended for the time being.

Walkamin Research Facility also conducted growth trials so see if there were any particular populations of this fish that performed better as a grow-out fish. This preliminary work did show that the northern strain have a different appearance and are much stockier than the southern strain. Pond reared fish, at 200 mm, the northern strain was 163 gms, while the southern was 137 gms. However the population from the Fitzroy-Dawson* catchments, did grow faster in captive conditions, on artificial feeds. (Brett Herbert AAQ Conference 2001.)
 * The Dawson River flows into the Fitzroy River. The Fitzroy River flows into the sea at Rockhampton. This population is well south of the nearest northern populations.

Summary of research as presented by the research scientist
Brett Herbert, at the AAQ Conference 2001

• The Fitzroy/Dawson River strain, grow better than northern strain for aquaculture.
• Recirculating systems necessary for grow-out.
• Must be stocked at high densities.*
• High fat diets, (15-20%) undesirable as the fat damages the liver, this will affect FCR because the liver is an important part of the digestive system.
• Placid and easy to handle.
• Fitzroy/Dawson strain genetically distinct from northern strain.
• Sleepy cod grow faster in tanks than in ponds
• Males grow slower.
• FCR 0.68-1.38
• Best above 26C. Below 22C not recommended, with problems below 18C**

Notes:

STOCKING DENSITIES.
The Marble goby is generally working in the 80 - 120 kg/m3 range (ie min-max density). are using oxygen generators to increase DO saturation to above 100%, this, along with high densities, is part of the recipe to successful growing of cod in general.

TEMPERATURE
They are very temperature tolerant. We have recorded temperatures in our ponds with brood fish, and small fingerlings, as low as 9c and as high as 35c. (We do not recommend handling them at low temperatures).  We routinely have broodstock in ponds during winter at temperatures as low as 21C and sometimes as low as 18C. During these cold times we are not able to handle these fish and do sometimes experience some minor losses. At temperatures above 21C we do not experience any difficulties.

They are very hardy and handle well, but do not handle well if temperatures are below 18c. Transport is easy as they live up to their name, "sleepy cod," and sit motionless in shipping containers. This results in low oxygen demand, and low ammonia production. Packing densities are still to be researched, but they should be very economical to ship live, packed densely, with a minimum amount of water.

WEANING
Fingerlings are easily weaned. Our fingerlings are not weaned as we believe it is better to ship the fingerlings soon after harvesting when they are in peak condition. They are raised in plankton ponds where they feed on natural food. We also believe that when weaned, then shipped, the stress results in a loss of confidence by the fingerlings in eating artificial food. They then need to be re-trained on to artificial food. The natural diet of sleepy cod is carnivorous. They feed on fish, freshwater shrimp and freshwater crayfish. They will therefore do best on a high protein diet similar to barramundi.

COLOUR
The colour of sleepy cod can change according to environmental conditions. No research has been conducted to determine how to manipulate their colour but it will be possible to provide fish to the market in a preferred colour once some trials have been carried out. Temperature and light will most probably be the factors that effect the fishes colour. They are capable of changing colour within a few minutes. Below are some examples of their ability to display a range of colours. These fish were all taken from the same pond at the same time.

CULTURE METHOD
The sleepy cod is not suitable for free-range pond culture as they are highly carnivorous and cannibalistic, as well as very territorial. They are able to eat other sleepy cod fingerlings up to half their size. It is necessary to grade fingerlings regularly. It is also possible for the fish to stop feeding on the artificial diet if they are in an open environment.

RAS Design Innovations

Our Marble Goby

Our major product is marble goby fry for fish farming and also mature marble goby for restaurant. Every aspect of the live fish from hatchery to harvest is traceable. We only issue the highest quality fish produced to our visitors and lovely customers.

Adult fish, fish fry, type, size, availability and price are depending on quantity buying, sending destination and current stock. (Photo that are shown below are for illustration purpose only.) Fries price are base on quantity buying, size or grade as below,

Fingerling

+ 1 inch fingerling fed by ice bloodworms
+ 2 inch fingerling fed by artificial feed (Eel floating feed)
+ 3 inch fingerling fed by artificial feed (Eel floating feed)
+ 4 inch fingerling fed by artificial feed (Eel floating feed)
+ 5 inch fingerling fed by artificial feed (Eel floating feed)
+ 6 inch fingerling fed by artificial feed (Eel floating feed)
+ upper 6 inch fingerling fed by artificial feed (Eel floating feed)

All fries are came from indoor fish farm and have been quarantine to ensure good quality during transportation to buyers.
 

We supply marble goby fries, but also free consultation on farming technique and help to sell back the adult fish with high price.

Mature Marble Goby
As required the weight from 400g ~ 1200g for restaurant using.

Recirculation Aquaculture Systems (RAS)

Recirculation Aquaculture Systems (RAS)
RAS represent a new and unique way to farm fish. Instead of the traditional method of growing fish outdoors in open ponds and raceways, this system rears fish at high densities, in indoor tanks with a "controlled" environment. Recirculating systems filter and clean the water for recycling back through fish culture tanks.

New water is added to the tanks only to make up for splash out and evaporation and for that used to flush out waste materials. In contrast, many raceway systems used to grow trout are termed "open" or "flow through" systems because all the water makes only one pass through the tank and then is discarded.

Fish grown in RAS must be supplied with all the conditions necessary to remain healthy and grow. They need a continuous supply of clean water at a temperature and dissolved oxygen content that is optimum for growth. A filtering (biofilter) system is necessary to purify the water and remove or detoxify harmful waste products and uneaten feed. The fish must be fed a nutritionally-complete feed on a daily basis to encourage fast growth and high survival.

BENEFITS OF RAS
RAS offer fish producers a variety of important advantages over open pond culture. These include a method to maximize production on a limited supply of water and land, nearly complete environmental control to maximize fish growth year-round, the flexibility to locate production facilities near large markets, complete and convenient harvesting, and quick and effective disease control.
+Intensive Production
+Water and Land Conserved
+Location Flexibility
+Species and Harvest Flexibility :RAS afford growers the opportunity to manipulate production to meet demand throughout the year and to harvest at the most profitable times during the year.

DISADVANTAGES OF RAS
+ They are relatively expensive systems to develop (building, tanks, plumbing, biofilters) and to operate (pumping, aerating, heating, lighting).
+ Moreover, they are complex systems and require skilled technical assistance to manage successfully.
+ Constant supervision and skilled technical support are required to manage and maintain the relatively complex circulation, aeration, and biofilter systems, and to conduct water quality analysis.
+ The danger of mechanical or electrical power failure and resulting fish loss is always a major concern when rearing fish in high densities in small water volumes.

THE RAS DESIGN
(1) growing tank,
(2) sump of particulate removal device,
(3) biofilter,
(4) oxygen injection with U-tube aeration,
(5) water circulation pump.

Depending on the water temperature and fish species selected, a water heating system may be necessary.

Ozone and ultraviolet sterilization also may be advantageous to reduce organic and bacteria loads.

WATER SUPPLY
A good supply of water, adequate in both quantity and quality, is essential to a successful fish farming enterprise, RAS or otherwise. Ground water obtained from deep wells or springs is the best source of water for fish culture. It generally is free of pollutants and has relatively high hardness levels, which are beneficial under some circumstances.

Municipal water supplies also can be used after chlorine, floride, and other chemicals are removed. Other sources of water, particularly surface waters from streams, rivers, ponds, and lakes, are not recommended for fish culture. Surface waters may contain fish diseases, parasites, pesticides, and other pollutants that can kill or slow the growth of fish. Testing the quantity and quality of the available water supply is one of the first steps for a prospective fish farmer to take to insure an adequate supply of high quality water.

BIOFILTER MEDIA
The ideal biofilter media has
(1) high surface area for dense bacterial growth,
(2) sufficient pore spaces for water movement,
(3) clog resistance,
(4) easy cleaning and maintenance characteristics.

We use and recommend plastic because it's lightweight, flexible, and easy to clean, but it can be expensive.

Most fish production recirculation systems are designed to provide at least one complete turnover per hour (24 cycles per day). Increasing the number of turnovers per day would provide increased biofiltration, greater nitrification (bacterial contact), and reduced ammonia levels.

FEEDS AND FEEDING
A complete feed, containing all the essential minerals and vitamins for healthy fish growth, and formulated specifically for the fish species being reared, is necessary for fish production in RAS. Do not substitute other animal feed for fish feed. Even different fish species have different nutritional requirements, particularly the quality and quantity of
protein needed, that must be met to optimize growth.

We recommend feeding a commercial feed of dry, floating pellets so that the feeding activity and health of the fish can be easily observed at the water surface. The size of the pellet should correspond with the size of the fish. Feed the largest pellet that the fish will readily swallow in order to maximize consumption and minimize waste. To keep feed fresh, order only a limited supply and store it in a cool, dry area, free of insects and rodents. In case of a liability problem with contaminated feed, it's a good idea to freeze small samples of each new batch of feed purchased for subsequent analysis if necessary.

If fish suddenly stop feeding, immediately check for high ammonia levels, low oxygen concentrations, diseases, or other problems. Reduced feeding rates occur at very high and low water temperatures. To maximize growth, feed on a regular schedule at the same time each day. More frequent feedings several times per day) have resulted in better growth rates and feed conversion efficiencies than a single daily feeding.

MARKET OPPORTUNITIES
A wide variety of freshwater fish can be farmed in RAS for a diverse number of purposes. Many species are commonly grown as food fish for marketing as live or processed products to wholesalers or retailers and directly to supermarkets and restaurants.

 

Marble goby

Oxyeleotris marmorata, the marbled sleeper or marbled gudgeon, or Soon Hock in Cantonese, is a widely distributed species of freshwater fish in the family Eleotridae. It lives in the Mekong and Chao Praya basins, rivers and other water bodies in Malaysia, Singapore, Indochina, Philippines and Indonesia. It is probably the largest Gobioid fish, reaching up to 65 cm (26 inch) in length.(Froese, Rainer and Pauly, Daniel, eds. (2012). "Oxyeleotris marmorata" in FishBase. November 2012 version.)

This species is an economically important fish in Southeast Asia, especially in Malaysia, Singapore, Thailand and Indonesia. It is highly popular among the Chinese community due to its fine texture, tasty white flesh and is believed to have healing properties. It is said, best eaten after surgeries or childbirths. Some says it can lead to prolonged life. In Malaysia, commercialization of this type of fish is not widely established. Demands are largely dependent on wild populations thus fetching high prices in the market.

This page was last modified on 21 March 2013 at 06:05.
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