Comprehensive guide to common diseases and troubles in marine fish, coral, reptiles, and tropical fish. Early detection is key.
Want to quickly identify a disease from symptoms? Use our Symptom Checker. Simply select symptoms to narrow down possible diseases.
White spots on body. Rubbing against surfaces. Rapid breathing.
Cryptocaryon irritans parasite. Often triggered by temperature drops or stress.
Cloudy body surface, excess mucus. Clamped fins. Loss of appetite.
Trichodina ciliate parasite. Often caused by poor water quality or overcrowding.
Gold to brown dust-like coating on body. Breathing difficulty. Rapidly worsening.
Amyloodinium ocellatum dinoflagellate. Progresses faster than ich with higher mortality.
White cauliflower-like growths on fins and body. Appetite usually maintained.
Viral infection. Triggered by stress or poor water quality. No direct cure; often self-resolves via immune response.
Red spots and ulcers on body. Pop-eye. Rapid deterioration.
Vibrio bacteria infection. Often enters through wounds. Risk increases with poor water quality.
Coral loses color and turns white. Polyp extension decreases.
High temperature, excessive light, sudden water quality changes. Loss of symbiotic zooxanthellae.
Tissue peels off rapidly within hours to days. White skeleton exposed.
Primarily bacterial infection. Triggered by water quality swings, introduction stress, or poor flow.
Tissue recedes more slowly than RTN. Bleaching spreads gradually from the base.
Chronic issues: nutrient buildup, insufficient light, low alkalinity.
Brown jelly-like substance on coral surface. Spreads rapidly to nearby corals.
Protozoan infection. More common on damaged or weakened coral.
Small brown worms cover coral surface. Reduced polyp extension. Color loss.
Flatworm parasites. Usually introduced with new coral. Preventable with dipping.
Old skin remains on toes, tail tip, around eyes. Can cause necrosis from poor circulation in severe cases.
Primarily insufficient humidity. Also poor nutrition, dehydration, or lack of rough surfaces in enclosure.
Jaw deformity, limb tremors, fractures. Severe cases cause difficulty walking.
Calcium deficiency, vitamin D3 deficiency, insufficient UV-B. Especially common in growing juveniles.
Open-mouth breathing, nasal discharge or mouth bubbles, loss of appetite, lethargy.
Keeping at too-low temperatures, sudden temperature changes, unsanitary conditions. Bacterial or fungal infection.
Swelling and redness around mouth. Cheesy pus inside mouth. Appetite loss. Unable to close mouth.
Bacterial infection. Often secondary to injuries (glass collision). Weakened immunity contributes.
Weight loss, diarrhea, losing weight despite eating. Worms may be visible in feces.
Internal parasites (nematodes, tapeworms) or coccidia. More common in wild-caught specimens.
Red hemorrhaging on body, raised scales (dropsy), bloating. Pop-eye.
Aeromonas bacteria. Always present but manifests with poor water quality or stress. Also damages internal organs.
White cotton-like patches on mouth, fins, body. Fin erosion. Whitened mouth.
Columnaris bacteria. More active at higher temperatures. Risk increases above 25C.
Multiple white spots on body and fins. Rubbing against objects. Appetite loss.
Ichthyophthirius multifiliis ciliate. Triggered by temperature drops or introducing new fish.
White fuzzy mold on body and fins. Common around wound sites.
Saprolegnia fungal infection. Usually secondary to wounds. More common at low temperatures.
Fin edges turn white and dissolve. Progresses toward the fin base.
Bacterial infection (Aeromonas, Columnaris). Caused by poor water quality, overcrowding, or stress.
This information is for general reference only. Always consult a veterinarian or specialist for actual diagnosis and treatment. If symptoms are observed, seek professional veterinary care as soon as possible.