How to tell if your Goldfish is sick

Worried your goldfish isn’t healthy? Here are a few guidelines for you.

First, if you’ve had your goldfish for a while, look for a change in behavior or appearance. Taking pictures of your goldfish is a good way to be able to keep track of what he looks like when he’s healthy.

If your fish is new to you, here are some symptoms to watch out for: 


Lethargy – not being as active as usual such as greeting you and following as you walk by his tank, exploring his tank, sifting through substrate

Less eager to eat – healthy goldfish should go right after food unless they have trouble finding it

Not eating at all – make sure the food has not gone bad and he’s eaten it before

Poop – normal goldfish poop is short and falls off quickly to the bottom of the tank, the color depends on the food but white or stringy poop is not normal, long strands of poop can mean overfeeding, no poop at all can mean constipation just like in all animals

Breathing fast – taking one breathing immediately after another without pause constantly

Yawning – just like we do – stretching the mouth wide open

Flashing – rubbing against ornaments or substrate, usually a quick dart not a back and forth rubbing

Clamping – most easily seen in the dorsal fin – held upright normally, holding it folded down against the body is not normal, can also be seen in pelvic fins being held against the body

Fin flicking – seen while clamped, stretching the dorsal fin upright then back down 

Floating in odd positions – swimming or floating with nose pointing up or down or completely upside down, healthy goldfish may point up or down briefly while swimming but at rest are horizontal

Small white spots on the body or fins usually in multiples – not to be confused with breeding tubercles on the gill plates – those are normal

Sores on the body – white or red spots, flat or raised     

Torn or irregular fins – healthy fins have smooth edges and heal quickly from minor tears

Red lines or splotches on fins or body – blood vessels/inflammation

Fuzzy white covering over all or parts of the fish

Bulging eyes – a change from what is normal for your fish or your fish’s breed, can be seen in one or both eyes

Swollen body, sometimes with a “pinecone” appearance to the scales meaning that the edges are raised up and no longer laying flat on the fish


If you see any of these symptoms or are just worried about your fish please ask for help! Post here in's "Illness and Disease Help" or contact a local fish veterinarian. We have experienced helpful members here to reassure you and recommend actions if necessary. Be careful of googling and treating without knowing what you’re dealing with.

Remember, the most common cause of illness in goldfish is poor water quality! Testing your water regularly with an API test kit and doing regular water changes can make all the difference.


Goldfish with ammonia burns and excess slime coat

An example of black discoloration after ammonia burn (red square) and excess slime coat (fuzzy white on edge of fish in blue rectangle)

Edited  by GingerFish