Goldfish is a small member of the carp family (Cyprinidae). It is called goldfish because it started from a gold variety of silver carp. They lack barbell which distinguishes it from common carp with two barbells.
Goldfish is one of the earliest fish to be domesticated and still one of the most commonly kept aquarium fish. It originated from China and introduced into Europe in the late 17th century. There are more than 100 beautiful varieties of goldfish at present which were developed by Korea, Japan, and China.
The average lifespan of goldfish in optimal conditions is 5-6 years but it may live for more than 20 years (the world record is 49 years).
Biology
* Goldfish are omnivorous and voracious eaters.
* They are egg-scatterers. Female lays adhesive eggs to breeding medium and male fertilizes the eggs (30 g breeder may lay 3,000 eggs).
* They spawn all year round, once every 15-20 days.
* They reach sexual maturity in 6-8 months old.
* They are sub-tropical species, live in freshwater with pH of 6-8, water hardness of 5-19 dGH and temperature range of 4-31 °C.
Different Varieties: Common, Shubunkin, Oranda, Ryukin, Lionhead, Dragon Eye, Pearlscale, Bubble Eye
Sexual Characteristics
Male: Edge of pectoral fin is smooth, no tubercles. Bulging urogenital opening
Female: Edge of pectoral fin with teeth-like serration and is rough. Depressed urogenital opening
Breeding Culture Method
A. Materials needed:
* Breeding tanks, concrete tank of aquarium
* Grow-out pond or tank
* Breeding medium made from polyethylene rope or yarn
* Aerator, basin, pail, scoop net, hose
B. Breeding procedure:
1. Fill-up breeding tank with water (30-35 cm), place breeding medium and aeration. If available, provide dripping water.
2. Place ready-to-spawn breeders (females ripe with eggs and males with running milt) at 5-10 fishes/sqm in tank or 10-25 fishes/50 gallon in aquarium. Sex ratio is 1:2 (male:female)
3. Early morning next day, inspect breeding medium. When eggs are present, remove the breeders to prevent them from eating the eggs.
4. Siphon out 50% of the water and replenish with freshwater. Place methylene blue (use dosage as indicated in the bottle) to prevent fungal attack of eggs.
5. Leave the set up until the eggs hatches in 36-48 hours. Aeration must be gentle.
6. When eggs are hatched, remove breeding medium. Siphon out shells of hatched eggs and unfertilized eggs. Do not feed yet.
7. After another 2 days when fry are free-swimming, feed the fry. Feed with newly-hatched Artemia or egg yolk of hard boiled egg for 7-10 days, 3-4 times a day.
8. Change water in tank or aquarium everyday at 30-40% exchange rate.
C. Grow-out culture:
1. Harvest fry in tank. Transfer the fry to grow-out hapa (1,000 fry/sqm) in pond and rear for 5-7 days. Feed with finfish fry mash.
2. Release the fry from hapa to grow-out pond (20-50 fry/sqm) after a week in hapa.
3. Feed with finfish fry mash (1st month) or crumble (2nd month) twice a day at satiation level.
4. Change water in pond once a week at 20-30% rate.
5. Cull the fishes 1-2 times before harvesting. Collect all fishes, cull out undesirable fishes (pale colored, deformed, abnormal) and return good quality fishes back to ponds.
6. Harvest the fishes after 2-3 months of culture (at least 2 inches body length).
7. Before transport, condition the fishes in tanks with flow-through water for 2-3 days. If flow-though is not available, change water at least 50% per day. Feed at a minimum amount twice a day.
8. Pack fishes in oxygenated plastic bag. Transport the fishes in the early morning or late afternoon.
Disease Treatment
Use commercially available treatment chemicals.
* For white spot disease/”ich” – 5 drops anti-itch (malachite green)/gal
* For Anchor worm – 5 drops anti-anchor worm (trichlorfon)/gal
* For bacterial infection – 5 ppm oxytetracycline or tetracycline HCL
* For fungus – 5 drops methylene blue/gal
Procedure
1. Add 1 teaspoon salt/gal water
2. Permanent (24 hrs) bath
3. Change water everyday
4. For 5-7 consecutive days
Note: During treatment, provide vigorous aeration and no feeding during treatment.
For more information, contact:
Ma. Theresa M. Mutia
National Fisheries Biological Center (NFBC)
Butong, Taal, Batangas
Telefax: (043) 421-1465
source: NFBC
