Diagnose a Problem
Start from the symptom you're seeing, not a guess at what's wrong. Each guide below works through the most likely causes in order of probability, with a clear line for when it's a simple husbandry fix and when it's genuinely time to call a vet. 25 symptom guides are planned across all five taxa; the guides below are live now.
How to use this page
Exotic and small-pet symptoms rarely map to a single cause the way a human symptom checklist might imply — a bearded dragon's blackened beard can mean thermoregulation, stress, or genuine illness, and a lethargic snake can mean anything from a normal pre-shed slowdown to a serious respiratory infection. Rather than pretending a single symptom always points to one diagnosis, each guide on this page walks through the realistic list of possible causes for that specific symptom, ranked from most to least likely, with the reasoning for each one spelled out rather than just named.
Every guide ends the same way: a clear, explicit answer to "is this something I can address with a husbandry fix tonight, or does this animal need to see a vet soon?" — because that's usually the real question a keeper searching a symptom actually has, not just a list of possible diagnoses with no guidance on urgency.
If you already know the specific problem your animal has (not just a symptom, but a named condition like impaction or metabolic bone disease), the disease and condition pillars go deeper on causes, treatment, and prognosis than a symptom-led guide can. If you know the exact species and the exact problem already, each species page also lists its own specific problem guides directly.
Reptiles
Your reptile has stopped eating or is eating noticeably less than usual.
Your bearded dragon's throat ('beard') has darkened to gray or black, either briefly during specific activities or for a longer, more persistent stretch of time.
Your chameleon has changed color in a way that seems unusual — very dark, very pale, blotchy, or a color pattern you haven't seen from it before.
Patches of old, dulled or whitish skin remain stuck to your gecko's body — commonly around the toes, tail tip, eye rims, or spine — after a shed that otherwise appeared to finish.
Your lizard's belly looks visibly rounded, distended, or firm compared to its usual shape, with or without other changes in behavior, appetite, or bathroom habits.
Your snake is moving less than usual, feels heavy or limp when handled, isn't exploring or responding to stimuli the way it normally does, or stays balled up in one spot for days at a time.
You hear an audible wheeze, click, whistle, or rattle when your snake breathes, or notice it holding its head raised at an unusual angle, breathing with its mouth open, or blowing bubbles of mucus from its nose or mouth.
Your tortoise has visible discharge from one or both nostrils, bubbling at the nose, or is wheezing, puffing the throat, or breathing with the mouth open.
Pressing gently on your turtle's shell (carapace or plastron) reveals give or flex where it should feel firm and rigid, or the shell has visibly thin, flexible edges.
Small Mammals
Wet, matted fur around your hamster's tail and hindquarters, possibly with lethargy or reduced appetite.
Your degu is drinking and urinating more than usual, and you're wondering whether this points to diabetes, cataracts, or something dietary.
Your ferret is sleeping more than its usual long baseline, is slow or reluctant to get up and play, seems weak on its hind legs, or is generally less responsive than normal.
Your guinea pig has thinning fur, bald patches, or areas of hair loss, with or without visible scratching, flaking, or crusting of the skin.
Your hedgehog is shedding noticeably more quills than usual, has visible bald or thinning patches, or you're finding loose quills scattered in the cage regularly.
Your rabbit has produced few or no fecal pellets in the last several hours to a day, especially alongside reduced appetite, hunching, teeth grinding, or reluctance to move.
Birds
Your bird has visible bald patches, thinning feathers, or you're finding more feathers than usual around the cage, and you need to work out whether this is normal molting or something that needs a vet.
Your budgie is sitting puffed up, quiet, and low on the perch instead of its normal alert, active self — the classic 'sick bird' presentation that needs fast triage.
Your cockatiel has started sustained, repeated screaming — distinct from its normal contact calls — and you want to know whether it's behavioral, medical, or something urgent.
Your parrot is eating noticeably less than normal, ignoring favorite foods, or has stopped eating entirely.
Amphibians
Your axolotl's external gill stalks look shrunken, curled, clamped flat against the head, discolored, frayed, or coated in something fuzzy or slimy, rather than the full, feathery, pink-to-red plumes of a healthy animal.
Your frog has visible reddening on its legs, belly, or webbing — a symptom picture that includes one of the most urgent conditions in captive amphibians.
Your toad has visible sores, red patches, open ulcers, unusual bumps, discolored blotches, or peeling/sloughing skin, rather than its normal even, bumpy, uniformly colored skin.
Invertebrates
Your hermit crab hasn't molted in what feels like an unusually long time, or you're comparing it to a tankmate that molts more often, and you want to know whether the gap is normal or points to a husbandry problem.
Your scorpion has repeatedly ignored or refused live prey over a period of days to weeks, and you're trying to work out whether this reflects normal scorpion biology or an actual problem.
Your tarantula has been sitting completely still, in the same spot or posture, for a stretch of time — anywhere from a day to several weeks — and you want to know whether this reflects ordinary tarantula behavior or signals something wrong.
When a symptom guide isn't enough
A symptom-led guide is a starting point for narrowing down what's likely going on and deciding how urgently it needs attention — it isn't a substitute for an in-person exam. Some conditions genuinely can't be told apart from a description alone (a swollen abdomen in a lizard could mean egg-binding, impaction, organ enlargement, or several other causes that look identical from the outside), and in those cases the honest answer in the guide itself is that a vet visit is the only way to actually tell them apart.
If more than one symptom is present at once — for example, not eating combined with lethargy, or discharge combined with labored breathing — treat that combination as more urgent than either symptom alone would suggest, even if each individual guide's urgency note reads as "routine" on its own.
This is general educational care information, not veterinary diagnosis. For a sick or injured animal, see a qualified exotic-animal vet promptly — especially for anything acute (not eating combined with lethargy, breathing changes, bleeding, or any sudden behavior change). Nothing on this page substitutes for an in-person exam.