Internal Parasites体内寄生虫

Symptoms

• White, translucent, stringy mucous faeces instead of normal formed brown droppings
• Appetite normal or even good while the fish still loses weight and the belly hollows out
• Darkened colour, hiding, stunted growth and sometimes pitting on the head
• In severe cases the fish hangs head-up and tail-down

Treatment, in order

1. 1 · IsolateIsolate and fast for a dayMove the fish to a hospital tank and fast it for 24 hours to confirm whether the droppings are mucous and white; fasting also reduces the organic load in the water.
2. 2 · Water changeChange water to improve qualityChange 30-50% of the water with matched temperature and clean the bottom. Flagellates can exist at low levels in healthy guts - water quality and stress are what turn them into a disease.
3. 3 · MedicationMetronidazole bath or medicated foodBath at 5-10 mg/L, redosing after each 30-50% water change every 24-48 hours for 7-10 days. It affects the biofilter, so keep treatment in the hospital tank where possible.
4. 4 · MedicationSwitch to praziquantel if tapeworms are suspectedIf tapeworm segments are seen trailing from the vent in addition to the white faeces, use praziquantel in food or as a bath at the label dose, repeating every 5-7 days.
5. 5 · FeedingFeed small meals during recoveryOnce feeding resumes, offer small frequent meals of good-quality food with vitamin supplementation; the gut lining needs 2-4 weeks to recover, so do not suddenly increase the ration.
6. 6 · ObserveWatch droppings and body conditionObserve for two weeks to confirm formed droppings and a filling belly; regaining weight is the final measure of success.

The standard treatment uses copper or formalin, which is lethal to corals, shrimp, snails and everything on live rock. Treat in a quarantine tank only, and leave the display tank fallow for the full period above before returning the fish.

Medications and cautions

Metronidazole

Hospital tank bath at 5-10 mg/L, redosed after each 30-50% water change every 24-48 hours for 7-10 days, or mixed into food at the label dose. It affects the biofilter, so finish the course in the hospital tank rather than medicating the display tank long term.

Praziquantel

For tapeworms and other helminths; use in food or as a bath at the label dose, repeating every 5-7 days. It is relatively gentle, but eggs are covered only by the repeat doses.

Prevention

• Quarantine new fish for 2-4 weeks and deworm during quarantine if needed
• Freeze or disinfect live foods instead of feeding them straight from an unknown source
• Store food cold and dry, and throw out anything that has gone mouldy

Frequently asked questions

What are the symptoms of Internal Parasites?

White, translucent, stringy mucous faeces instead of normal formed brown droppings; Appetite normal or even good while the fish still loses weight and the belly hollows out; Darkened colour, hiding, stunted growth and sometimes pitting on the head; In severe cases the fish hangs head-up and tail-down. It usually starts with: New fish carrying the parasite, sharing water with infected fish; Long-term feeding of live or untreated raw foods; Poor water quality, overcrowding or stress after transport.

How do you treat Internal Parasites?

In order: 1. Isolate and fast for a day (Move the fish to a hospital tank and fast it for 24 hours to confirm whether the droppings are mucous and white; fasting also reduces the organic load in the water.) 2. Change water to improve quality (Change 30-50% of the water with matched temperature and clean the bottom. Flagellates can exist at low levels in healthy guts - water quality and stress are what turn them into a disease.) 3. Metronidazole bath or medicated food (Bath at 5-10 mg/L, redosing after each 30-50% water change every 24-48 hours for 7-10 days. It affects the biofilter, so keep treatment in the hospital tank where possible.) 4. Switch to praziquantel if tapeworms are suspected (If tapeworm segments are seen trailing from the vent in addition to the white faeces, use praziquantel in food or as a bath at the label dose, repeating every 5-7 days.) 5. Feed small meals during recovery (Once feeding resumes, offer small frequent meals of good-quality food with vitamin supplementation; the gut lining needs 2-4 weeks to recover, so do not suddenly increase the ration.) 6. Watch droppings and body condition (Observe for two weeks to confirm formed droppings and a filling belly; regaining weight is the final measure of success.)

Is Internal Parasites contagious, and how urgent is it?

Contagion: low contagion. Severity: moderate. Cause: parasite. Not an emergency, but do not ignore it. It will not kill overnight, yet it is a common cause of chronic wasting, and neglect drags on for weeks.

What medication treats Internal Parasites?

Metronidazole: Hospital tank bath at 5-10 mg/L, redosed after each 30-50% water change every 24-48 hours for 7-10 days, or mixed into food at the label dose. It affects the biofilter, so finish the course in the hospital tank rather than medicating the display tank long term.; Praziquantel: For tapeworms and other helminths; use in food or as a bath at the label dose, repeating every 5-7 days. It is relatively gentle, but eggs are covered only by the repeat doses.

Is the treatment for Internal Parasites safe for corals and inverts?

No. The standard treatment (copper or formalin based) is lethal to corals, shrimp, snails and everything on live rock. Treat in a quarantine tank only, and leave the display tank fallow for the full period given above.