AquaPulse Tools · Free web tool
Aquarium Emergency Diagnosis
A few quick questions help you prioritise what to check when something looks wrong. This tool doesn't diagnose a disease or recommend medication — it ranks the common, plausible causes for what you're seeing and gives you sensible, safe next steps, in the same spirit as NHS symptom guidance or Mayo Clinic triage. Runs entirely in your browser — no login, no account, nothing saved or sent anywhere. Prefer to read at your own pace instead of answering questions? Browse the Fish Symptoms hub for symptom-by-symptom guides.
Emergency diagnosis tool
Your assessment
Answer the questions and press “Get my assessment” to see the most likely causes, what to check first, and links to relevant guides.
About this tool
What it does
Asks what you're seeing, how long it's been happening, and (optionally) how your water readings compare with normal. It then ranks the common, plausible explanations, using confidence wording like “high likelihood”, “possible” and “worth checking” — never a percentage, and never a single confident answer.
What it deliberately won't do
It never names a specific disease with certainty, never recommends a medication or dose, and never tells you what your fish "has". Water quality, observation, verification and knowing when to bring in a specialist matter more than a fast label.
Why the causes are ranked, not ruled
Several explanations can look identical from the outside. When more than one is similarly likely, the assessment says so directly rather than picking one arbitrarily — investigating a short list is usually safer than committing to a guess.
Why testing your water helps, but isn't required
A described symptom alone gives a reasonable starting point. Adding ammonia, nitrite, nitrate and temperature readings refines which causes are promoted and which checklist items appear, but every step still works if you choose "No" or "Unknown".
Want the full picture?
This tool handles quick triage. For the detailed reasoning behind a specific symptom, browse the Fish Symptoms hub to find the guide that matches what you're seeing — including fish gasping, fish dying one by one, white spots, velvet disease, fin rot, fungus or columnaris, dropsy, ammonia and nitrite — or see our dedicated guides to cloudy water or bad smells, or browse the full Knowledge Centre.
Good to know: This tool provides general informational guidance only. It does not diagnose disease, does not recommend medication or dosing, and does not replace testing your own water or consulting a vet or aquatic specialist for serious or persistent livestock health issues.
Keep this alongside your tank's history
This assessment is based on what you described just now. If you're testing your water as part of working through it, AquaPulse can keep those readings together over time, so if something similar happens again you're comparing against your own tank's pattern instead of starting from nothing.
It doesn't diagnose, and it isn't a symptom tracker — it's a place to keep water-test history, separate from this assessment.
Common questions
Frequently asked questions
Does this tool diagnose what's wrong with my fish?
No. It ranks the most common, plausible explanations for the symptom you describe and suggests sensible next steps — it never names a specific disease with certainty or tells you what your fish "has". For a confirmed diagnosis, a vet or experienced aquatic specialist who can examine the animal is the right next step.
Will it tell me what medication to use?
No. This tool never recommends a medication or a dose. Medicating before you understand what's happening can mask symptoms, harm livestock, or damage your biological filter — the checklist focuses on water quality, observation and verification instead.
What if my symptom isn't listed?
Choose "Something else" for a general checklist covering water testing and recent changes, and browse the Knowledge Centre, which covers many specific symptoms and water-quality topics in more depth.
Do I need to test my water before using this?
No — testing is optional. Without a test, the tool works from your symptom and how long it's been happening. Adding ammonia, nitrite, nitrate and temperature readings refines the result but never blocks it.
Is this a substitute for veterinary advice?
No. It provides general informational guidance only. For severe, persistent or worsening symptoms, or unexplained losses, contact an aquatic veterinarian or a suitably experienced specialist.