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Start with one clear photo
Use a photo of your fish as the first input when you notice spots, torn fins, swelling, unusual swimming, or color changes.
Fish Disease Identifier app
Turn One Fish Photo Into Clear Next Steps.
Take one clear photo in Fish Disease Identifier and get likely disease matches, possible causes, and practical next steps when something looks wrong in your aquarium.
Educational guidance only. Not veterinary advice.
Not sure what is wrong with your fish? Start with the symptom checklistBuilt for aquarium owners using Fish Disease Identifier to compare sick fish photos, visible symptoms, and saved scans.
Fish Disease Identifier photo scansLikely matches in secondsNext steps to considerBuilt for aquarium owners
Why Download It
Three fast reasons to use Fish Disease Identifier.
Start with a photo, compare likely matches, and know which checks matter next.
02
Get likely disease matches
See possible issues such as ich, fin rot, swim bladder problems, fungal infections, or water-quality stress.
03
Know what to check next
Get practical next checks like water parameters, visible symptoms, urgency signs, and care steps to consider.
After the scan
What Fish Disease Identifier gives you after a photo.
The app turns one fish photo into a practical result you can compare against visible symptoms and tank conditions.
Likely issue
Possible disease matches
Compare the photo against common problems such as ich, fin rot, bloat, swim bladder issues, parasites, or water-quality stress.
Reasoning
Visible signs used
See which visible clues matter most, including spots, fins, swelling, eye changes, breathing, posture, and swimming behavior.
Priority
Urgency and severity cues
Separate mild changes from warning signs such as gasping, pineconing scales, open sores, collapse, or fast decline.
Next checks
What to verify in the tank
Get practical checks for water parameters, recent changes, new fish, food, tank mates, and whether expert help is needed.
Common Fish Disease Guides
Start with the disease names aquarium owners search first.
Image: Thomas Kaczmarczyk / Djpalme / Public domain / resized and cropped for layout
Disease guide
Ich in Fish (White Spot Disease): Signs and What to Do
Use this disease guide when distinct salt-grain spots plus rubbing, clamped fins, or faster breathing make ich a likely match. If the marks are fuzzy, dusty, flat, or still unclear, start with the broader white-spots symptom guide instead.
Key signs
- Distinct salt-like white grains on fins, body, or near gills.
- Flashing, rubbing, clamped fins, or sudden irritation.
First check: Compare salt-like grains with dust, fuzz, and bubbles.
Same-day concernRead guide
Image: Andrew Sheedy / CC BY-SA 4.0 / resized and cropped for layout
Disease guide
Fin Rot in Aquarium Fish: Signs, Causes, and Next Steps
Fin rot is a possible match when ragged or discolored fin edges keep shrinking toward the body. A single clean split after chasing or contact with decor fits the torn-fins symptom guide more closely.
Key signs
- Ragged, uneven, shrinking, pale, red, or dark fin edges.
- Fin clamping, hiding, lower appetite, or reduced activity.
First check: Check water, nipping, and whether fin loss is spreading.
Monitor closelyRead guide
Image: Humanfeather / Michelle Jo / CC BY 3.0 / resized and cropped for layout
Disease guide
Fish Floating Sideways: Swim Bladder Disease or Something Else?
Swim bladder problems can cause floating, sinking, rolling, or difficulty staying level. The visible behavior is a clue, not certainty.
Key signs
- Floating, sinking, rolling, nose-up, tail-up, or sideways posture.
- Excessive fin effort to stay level.
First check: Check water, feeding history, swelling, and posture.
Monitor closelyRead guide
Image: Citron / Public domain / resized and cropped for layout
Disease guide
Dropsy in Fish: Swollen Belly, Pineconing Scales, and Warning Signs
Dropsy describes swelling and fluid imbalance rather than one single disease. Pineconing scales, severe bloating, and lethargy can be serious warning signs.
Key signs
- Raised scales that look pinecone-like from above.
- Sudden or severe body or belly swelling.
First check: Look from above for pineconing scales.
Same-day concernRead guide
Image: Mydigitalife / CC0 / resized and cropped for layout
Disease guide
Velvet Disease in Fish: Dusty Coating, Fast Breathing, and Next Checks
Velvet may look like a fine gold, rust, or dusty coating and can affect the gills. It can progress quickly, so breathing signs deserve attention.
Key signs
- Fine gold, rust, tan, or dusty coating visible under angled light.
- Rapid breathing, surface hanging, or staying near high flow.
First check: Use angled light and check breathing immediately.
Emergency checkRead guide
Image: Rjcastillo / CC BY 4.0 / resized and cropped for layout
Disease guide
Cloudy Eye in Fish: Causes, Checks, and Next Steps
Cloudy eye can be a symptom of injury, water stress, infection, or irritation. One cloudy eye often suggests trauma, while both eyes can point toward system-wide stress.
Key signs
- Milky, hazy, scratched, or filmed eye surface.
- One or both eyes may be affected.
First check: Check one eye vs both eyes and test water.
Monitor closelyRead guide
Symptom Guides
Start with what you can see in the tank.
Image: Thomas Kaczmarczyk / Public domain / resized and cropped for layout
Symptom guide
White Spots on Fish: Ich, Fungus, or Something Else?
Start here when you can see white marks but do not yet know the cause. Compare grains, dust, fuzz, flat patches, behavior, breathing, and water tests before opening a disease-specific guide.
Key signs
- Distinct salt-like grains on fins, body, or near gills.
- Rubbing, flashing, clamped fins, or hiding.
First check: Compare grains, dust, fuzz, and bubbles under angled light.
Same-day concernRead guide
Image: Denise Chan / CC BY-SA 2.0 / resized and cropped for layout
Symptom guide
Torn Fins on Fish: Nipping, Injury, or Fin Rot?
Start here for unexplained torn, split, or frayed fins. Clean sudden tears often fit nipping or injury, while shrinking, discolored edges that worsen over time make fin rot a more useful comparison.
Key signs
- Clean splits, missing fin pieces, ragged edges, or shrinking fin margins.
- Pale, dark, or red fin edges may suggest irritation or infection.
First check: Check nipping, sharp decor, filter intake, and water.
Monitor closelyRead guide
Image: Humanfeather / Michelle Jo / CC BY 3.0 / resized and cropped for layout
Symptom guide
Fish Floating Sideways: Possible Causes and Next Steps
Floating sideways is a buoyancy sign, not a single diagnosis. It can range from digestive pressure to serious systemic illness.
Key signs
- Floating sideways, upside down, nose-up, tail-up, or sinking.
- Trouble holding position or reaching food.
First check: Check swelling, feeding history, posture, and water.
Same-day concernRead guide
Image: Citron / Public domain / resized and cropped for layout
Symptom guide
Swollen Belly in Fish: Possible Causes and Warning Signs
Belly swelling can be mild or serious. Pineconing scales, lethargy, and appetite loss are important warning signs.
Key signs
- Round belly, uneven swelling, or full-body bloating.
- Raised scales from above, appetite loss, hiding, or lethargy.
First check: Use a top-down view to check for pineconing.
Same-day concernRead guide
Image: Mitternacht90 / Public domain / resized and cropped for layout
Symptom guide
Fish Gasping at the Surface: Causes and Urgent Checks
Surface gasping can signal an urgent oxygen, ammonia, nitrite, heat, or gill problem. Increase aeration and check water promptly rather than waiting for a clearer photo match.
Key signs
- Mouth opening repeatedly at the surface or filter outflow.
- Multiple fish crowding high-flow or high-oxygen areas.
First check: Test ammonia/nitrite and increase aeration immediately.
Emergency checkRead guide
Image: SOK / CC BY-SA 4.0 / resized and cropped for layout
Symptom guide
Rapid Breathing in Fish: Possible Causes and Next Checks
Rapid breathing is often more urgent than external spots because gill or oxygen problems can worsen quickly.
Key signs
- Gill covers moving faster than normal for the species.
- Fish stays near flow, hides, clamps fins, or stops eating.
First check: Test ammonia/nitrite and check oxygenation.
Same-day concernRead guide
Start with what you see
Direct guides for urgent signs and easy-to-confuse patterns.
Start with the visible symptom when the cause is unclear, or open a disease guide when the pattern already fits.
Disease guide
Ammonia Poisoning in Fish: Red Gills, Gasping, and Emergency Checks
Ammonia poisoning is a possible cause of sudden gasping, red gills, lethargy, or several fish declining together. Test ammonia and nitrite immediately because a photo cannot confirm or rule out toxic water.
Symptom guide
Fish Gasping at the Surface: Causes and Urgent Checks
Surface gasping can signal an urgent oxygen, ammonia, nitrite, heat, or gill problem. Increase aeration and check water promptly rather than waiting for a clearer photo match.
Symptom guide
Red Gills on Fish: Ammonia, Oxygen, or Parasites?
Sudden red or inflamed gills plus fast breathing can point to ammonia, nitrite, low oxygen, heat, or gill irritation. Test the water and check aeration promptly, especially when several fish are affected.
Symptom guide
Lethargic Fish: Causes, Warning Signs, and First Checks
A lethargic fish may be resting, stressed, or unwell. First check whether the change is sudden and whether one fish or the whole tank is affected, then compare breathing, appetite, posture, and visible body signs.
Disease guide
Fin Rot in Aquarium Fish: Signs, Causes, and Next Steps
Fin rot is a possible match when ragged or discolored fin edges keep shrinking toward the body. A single clean split after chasing or contact with decor fits the torn-fins symptom guide more closely.
Symptom guide
Torn Fins on Fish: Nipping, Injury, or Fin Rot?
Start here for unexplained torn, split, or frayed fins. Clean sudden tears often fit nipping or injury, while shrinking, discolored edges that worsen over time make fin rot a more useful comparison.
Disease guide
Ich in Fish (White Spot Disease): Signs and What to Do
Use this disease guide when distinct salt-grain spots plus rubbing, clamped fins, or faster breathing make ich a likely match. If the marks are fuzzy, dusty, flat, or still unclear, start with the broader white-spots symptom guide instead.
Symptom guide
White Spots on Fish: Ich, Fungus, or Something Else?
Start here when you can see white marks but do not yet know the cause. Compare grains, dust, fuzz, flat patches, behavior, breathing, and water tests before opening a disease-specific guide.
High-Intent Help
Not sure where to start?
These pages connect urgent aquarium questions to Fish Disease Identifier, practical checks, and app downloads.
What's Wrong With My Fish?
A direct starting point for spots, swelling, gasping, strange swimming, or appetite changes.
Fish Disease Identifier App
How the mobile app works and why results are possible matches, not guaranteed diagnoses.
Fish Symptom Checker
Move from visible symptom to possible causes, checks, and next steps to consider.
FAQ
A few quick answers
Can Fish Disease Identifier diagnose my fish with certainty?
No. The app provides likely matches and possible causes from a photo. Fish disease symptoms can overlap, and photo quality, lighting, water conditions, and species differences can affect results.
Is this veterinary advice?
No. Fish Disease Identifier is educational and should be used as a starting point. For severe, worsening, or unclear symptoms, contact an aquatic veterinarian or experienced aquarium professional.
What makes a good scan photo?
Use a sharp, well-lit photo where the fish is visible from the side. Avoid glare, heavy blue lighting, motion blur, and reflections.
What should I check besides the photo?
Check recent water changes, ammonia, nitrite, nitrate, temperature, pH, tank mates, new fish introductions, food changes, and visible behavior changes.
Can the app help with treatment?
The app can suggest practical next steps to consider, but you should verify treatment choices with trusted aquarium references, product labels, or a qualified professional.
Fish Disease Identifier
Still not sure what your fish has?
Scan a photo in Fish Disease Identifier and get likely disease matches, possible causes, and next steps to consider.
Educational only. Not veterinary advice.