Common Symptoms of Sick Fish
Below are some common symptoms of a sick fish and some related possibilites.
My fish is scratching on things?
Is your fish scratching against tank decorations, rocks or sides of the tank? Is he flashing the top of the water? Does it look like he's trying to rub something off his scales? If so please read up on Parasites, they are usually something visual.
Can you see something on your fish's body or fins?
Are there are visible spots, lesions, lumps, or white patches on the fish's body or fins. Are his fins jagged and looked worn down? Are the fish's tail or fins appear frayed at the edges or are breaking off, disappeared? In these cases you usually have a type of parasite (I can see something on my fish) or bad water parameters (Jagged fins or red steaking). Sometimes the water conditions can reach a critacal stage where the ammonia in the water actually eats away at the fish. Usually sores are caused by two things. One is a physical wound healing, maybe a bite from another fish. The second is a type of bacterial infection that causes the sore.
Red streaks near scales
Does you fish suddenly have visiable red streaks on it's body? This is a good indication of bad water parameters.
My fish can't breath!
Is your fish gasping at the surface of the water. There's probably an issue with his water (duh), usually it's after a water change where the oxygen level's he's used to have changed or some other water metric.
Gills that are puffy or swollen
Do your fishes gills look puffy or swollen? Is the gill tissue is bright red or even a grayish color? This is a good indication that something is wrong with your water.
The fins are not stretched out and wide open, as it normally will. Parasitism or water quality [especially pH crash] account for this. Clamped fins can be a very vague finding and usually means you have time to find out what's going on. Fish with clamped fins are ONLY unhappy, not about to die.
My fish is FAT, HUGE!
Fish suddenly becomes really fat. Fish who suddenly become huge are usually in the middle of some type of internal digestion problem. Most common is called dropy, but it can be related to a number of bacterial infections.
My fish is laying on the bottom!
Usually when a fish crashes to the bottom of your tank he is in his last throws. He no longer had the energy to swim and doesn't have much longer to live.
My fish won't eat!
The fish refuses its usual food for more than 2 days. The cause of a loss of appetite in tropical fish is most commonly stress. New fish which have just been introduced to a new aquarium are prime candidates to exhibit a loss of appetite. Your tropical fish can also feel a great deal of stress due to overcrowding. If you have just introduced new fish into the aquarium and the original ones are exhibiting signs of stress this may be the case.
My fish is acting weird.
Is your fish hiding? Is the fish floating, sinking, whirling, or swimming sideways? A normally active fish is still. A normally still fish is very active.
Disease & Tank Problems
Common Problems(80% of all problems aquarium issues)
New Tank Syndrome - Is your tank new? Do you have cloudy water?
Ammonia Poisoning - Fins are torn, red steaking on body.
Vitamin Deficiencies - Scoliosis (Curved Spine), Reduced Growth, Lack or Loss of Appetite
Bad Water - Gravel washed this week? Add new water? See Ammonia Poisoning
Swim Bladder Problems - Erratic Swimming Position, Loss of equilibrium.
Physical Injury - From fighting, bumping into things, etc
Stress - Acting weird? Hiding all day? Not eating?
Walmart Syndrome - Did you buy your fish there?
Parasites(Usually visual things/bugs)
Anchor Worms - Tiny white-green or red worms in wounds, Frequent rubbing or "flashing".
Black Spot - Small black speckles on body.
Ich - Small white "salt-like" pimples on fins & body.
Skin / Gill Flukes - Fish gasps for air at the water's surface, gills covered in mucus.
Oodinium (velvet) - Fine grey-gold to whitish 'dust' on the body.
Parasites (External) - Large ugly sores on body.
Planaria - Small White Hairlike Worms in the tank.
Bacterial Diseases(Mostly Internal Problems or invisable problems)
Pop Eye - One or both eyes protrude from the head in an unusual fashion.
Dropsy - Huge, Fat, Bloated Belly, Lethargy and loss of appetite.
Fin Rot - Fins turn Jagged or whitish and die back.
Hole in the Head - Small holes in and around the head.
Fungal(Usualy white foggy type things)
Cataracts - White or grey "foggy" eyes.
Cotton Mouth - White "Cotton like" fungus on the mouth.