Asian seabass (barramundi)Lates calcariferSeed is easy to find, but cannibalism is severe under 10 cm.
Grouper (orange-spotted, tiger, pearl)Epinephelus spp.Has the best nursery manual. Prone to viruses and needs frequent grading.
Cobia (cá giò)Rachycentron canadumGrows very fast and has the largest seed size. Needs heavy water exchange.
Golden pompano (long and short-finned)Trachinotus blochii, T. ovatusThey do not stop eating when full. Two species share the name.
Red drum (cá đù đỏ)Sciaenops ocellatusPrefers cooler water and survival falls above 29 °C. Highly prone to Amyloodinium.
RabbitfishSiganus guttatusA plant-leaning omnivore that needs far less protein. Fin spines are venomous.
Seed sizes in the regulation
From QCVN 02-36:2021/BNNPTNT. Seabass, rabbitfish and hybrid grouper are not covered.
Small fingerling (cá hương)Fingerling (cá giống), from the minimum up
Brown-spotted grouper
1.5–7≥ 7 cm
Cobia
4–10≥ 10 cm
Pompano, long-finned (T. blochii)
2–5≥ 5 cm
Pompano, short-finned (T. ovatus)
2–5≥ 5 cm
Red drum
3–5≥ 5 cm
02468101214
| Species | Small fingerling, cm | Small fingerling, g | Fingerling | Reference age (days) |
|---|---|---|---|---|
| Brown-spotted grouper | 1.5 to under 7 | 1 to under 6 g | from 7 cm, from 6 g | 30 / 70 |
| Cobia | 4 to under 10 | 2 to under 8 g | from 10 cm, from 8 g | 20 / 60 |
| Pompano, long-finned (T. blochii) | 2 to under 5 | 0.8 to under 6 g | from 5 cm, from 6 g | 25 / 35 |
| Pompano, short-finned (T. ovatus) | 2 to under 5 | 0.8 to under 7 g | from 5 cm, from 7 g | 25 / 35 |
| Red drum | 3 to under 5 | 1 to under 4 g | from 5 cm, from 4 g | 35 / 45 |
Age: the first figure runs from first feeding to the small fingerling stage, the second from the end of that stage to the fingerling stage, both reference minimums. Deformity: at most 2% for small fingerlings and 1% for fingerlings.
Quick comparison
Figures are from the species pages, with sources there. Each cell is one published figure, not a promise.
| Species | Feed | Grading | Transfer size | Watch out for |
|---|---|---|---|---|
| Seabass | Live feed then pellets, wean from about 16 mm | 5–7 days, separate at 30–33% difference | 12 cm and up (Quang Ninh) | Cannibalism |
| Grouper | Pellets, 50–52% protein | 3 days to over a week, under 30% spread | 5–10 cm (ACIAR); 12–20 cm in Kien Giang | VNN, iridovirus |
| Cobia | Micro-diet, over 55% protein | 5–20 days by size | 10–12 cm | Amyloodinium |
| Pompano | Pellets, never to satiation | Pull shooters; lots within about 1 cm (1 cm: short-finned) | 6–8 cm (Quang Ninh) | Two species, one name |
| Red drum | Crumble, 45–50% protein | No fixed interval found | 10 cm and up (Quang Ninh) | Heat above 29 °C, Amyloodinium |
| Rabbitfish | 35–37% protein, algae can be added | Not yet known | 30–50 g | Venomous spines, needs shade |
Why these six
A 2022 extension paper says only about 4–5 species are produced in volume: seabass, pompano, red drum, hybrid grouper and cobia. Rabbitfish was added because it has a standard and pilot models in central Vietnam. Mangrove red snapper and milkfish are left out for now because nursery data is thin or not close to Vietnam.