Fish disease protocols
Six protocols, decided by eye
Built from Than Vuong's field experience document — 134 real situations, none of which needs an antibiogram. Look at the fish, the water, open a few, then follow the matching protocol.
Start here
Match the sign to a protocol
This table stands in for lab work. If two groups of signs appear together, go straight to the co-infection protocol.
| What you see | Most likely | Protocol |
|---|---|---|
| White pus spots on liver, kidney, spleen | Bacillary necrosis (Edwardsiella ictaluri) | Open → |
| Red fin bases and vent; skin haemorrhage; ulcers | Haemorrhagic septicaemia (Aeromonas) | Open → |
| Both internal pus spots and external haemorrhage | Co-infection — assess the ratio first | Open → |
| Pale liver and gills after several antibiotic courses | White liver, white gill from antibiotic overuse | Open → |
| Startling while feeding; mucus loss; small tight groups | External parasites — gill flukes, Trichodina, anchor worm | Open → |
| Undigested faeces, poor appetite, slow growth | Internal parasites and digestive upset | Open → |
Six protocols
One page per condition
Two protocols use no antibiotic at all, and are labelled as such. Most situations at the pond belong there.
QT-01
Bacillary necrosis
This one cannot be judged from the outside. Open 5–10 fish to see the white pus spots on liver, kidney and spleen — the only reliable sign.
QT-02
Haemorrhagic septicaemia
Unlike bacillary necrosis, this one shows from the outside: redness at the fin bases, around the vent and on the flank.
QT-03
Co-infection: haemorrhage and bacillary necrosis
Usually appears after a first course that did not clear. The document names the cause plainly: a dragged-out treatment and repeated antibiotic courses.
QT-04No antibiotic
White liver, white gill from repeated antibiotics
Farmers often mistake this for a fresh bacterial infection and feed more antibiotic, deepening the loop.
QT-05No antibiotic
External parasites
The sign is behaviour before it is a lesion: startling during feeding, and gathering into small groups swimming through each other.
QT-06
Internal parasites and undigested faeces
Deworm on a schedule rather than waiting for symptoms. It is the cheapest prevention in the whole crop.
Ground rules
Six rules in place of an antibiogram
Without a lab, you need discipline. These six come from the document itself — from what worked, and from two situations where it records what went wrong.
01
Environment first, antibiotics after
In all 134 documented situations, no protocol opens with an antibiotic.
02
Clear parasites before treating bacteria
With parasites present, antibiotics do not hold — the most repeated cause in the document.
03
Full dose, full course
Stopping as soon as the fish improve is the surest way to lose the drug next time.
04
Combining two drugs takes the longer withdrawal
FLOR-MAX 12 days, DOXYPA 4 weeks. Combined, count 4 weeks — check it against the harvest date before you start.
05
Do not mix DOXYPA with minerals in the same feeding
Doxycycline binds calcium and magnesium, cutting absorption. Give QUICKSHELL GOLD, MIXBOOM, CANFORTA at another feeding.
06
No improvement in 3–5 days: stop, do not raise the dose
Re-check the diagnosis and the environment. Never run a third antibiotic course on one pond in one crop.