General Problems
New Tank Syndrome
Symptoms
- Fish losses in the first 4–8 weeks of a new tank
- Detectable ammonia or nitrite despite water changes
- Cloudy water, sluggish or hiding fish
Likely causes
- Adding livestock before the biofilter is established
- Stocking too many fish at once
- Insufficient or improperly seeded filter media
Immediate steps to take
- Dose a bottled bacteria starter daily for one week
- Do small daily water changes (20%) until ammonia and nitrite read zero
- Use a detoxifying conditioner like Seachem Prime every 24 hours
- Stop feeding for 48 hours and only feed lightly afterwards
Long-term prevention
- Cycle every new tank fully — dose pure ammonia to 2 ppm and wait until it processes to 0 within 24 hours, with 0 nitrite, for a week
- Seed new filters with media from an established healthy tank
- Stock slowly — one or two small fish at a time, weeks apart
Recommended products & practices
There is no shortcut to a cycle, but a quality bacterial starter plus patience makes the wait shorter and the losses zero. Plan for 4–6 weeks before any livestock.