Aquarium tropical fish and fish diseases


Aquarium tropical fish disease diagnostics

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This web-tool allows your to perform quick interactive diagnostics of your aquarium or pond fish mostly based one on how they look like and how they behave. In the full description of a disease you can find additional information about it as well as information on treatment and preventing of it.

You can browse the list of fish diseases

Please, specify all symptom (external body conditions and specific behaviour) which you are observing on your fish. There must be no less than 2 symptoms. If unsure whether symptom is present - mark it!

You should know, that diagnostics is made only merely on whether symptom is present or absent for each disease. Each symptom for each disease in the databse has its weight and diagnostics is made using these weights. Determination of correct weights is the most important point. We have collected a lot of data through many books and sites to determine the weights. However, this data never be perfect, so, when you perfom diagnostics be sceptical and analyze what you read in full desriptions of diseases. As you understand, we do not take any responsibility on what you would do with you fish in any case. Use this tool solely on your own risk. But we think it is better thank nothing and does help in many cases.

Exterior (body conditions):

Ashy coloring
Big tumour in the area of throat

Black discoloration of the iris
Black spots
Bloated front part of belly

Bloody spots turning into ulcers with white edge and red center

Bloody-redish wounds
Blue-grayish slime coating
Blue-white opacification of fin edges
Brightening (lighting) of body colors
Constantly open mouth
Cotton wool coating

Darkening of body color (Black discoloration)
Darkening of gill filaments
Decay and fading of tail fin
Degeneration of gonads
Degradation of gills
Development of gonads
Entire body covered whith gray coating
Fins are spread apart
Fins stick together
Fish growth slows down
Fish stop growing
Fish swim near the surface, often holding the dorsal fin above the water
Flat black overgrowth on skin and fins
Fraying of fins
Gill covers are bent
Granular structure of the iris (Pterophyllum scalare only)
Gray stripes on gills
Grayish-whitish tumour excrescence 1-5 mm on fins, gill covers and on the edge of the mouth
Heavy slime production
Hemorrhage in eyes
Hemorrhages around the nostrils and in gill covers
Hemorrhages on the body and fins

Inflamed anus
Inflammation of eyes
Leukoma (spot on an eye)
Loss of eyes
Mosaic gills coloring
Opacification of the cornea (keratoleukoma, nebula)
Overall body thinness
Paralysis of dorsal and pictorial fins
Popped eyes
Protruding operculi (gill covers)
Ragged or frayed dorsal fin
Rectum and bladder are partially fallen out
Red stripes on gills
Round and oval pale or pink bumps between 5 and 10 mm in size

Scale raising
Scale shedding
Scoliosis (bent spine)

Separate slightly red areas on the body
Separation of fin rays
Shiny stripe of NEON lost color on some parts of the body
Skin became transparent because of very enlarged belly
Skin became whitish in the area of dorsal fin and tail stem
Skin detaching
Skin thickening
Slime comes out of gills
Small dark spots
Swelled gill filaments
Tail fin is down
Thin white thread on the ROE
Tumours near tail, ventral and pectorial fins
Underdevelopped fins
Underdevelopped gill covers
Uneven (rough) gill edges
Velvety coating flour like coating

Very small white and gray nodules
Very small whitish-yellowish spots
Very thin white threads perpendicular to a body

Warts tear apart when you try to separate them
White and gray nodules (spots)

White gills
White spots small white bumps

White ulcers near the base of disintegrated fins

Whitish bursting/opening spots and tumours
Whitish spots


Clamped fins
Dead fish stay with open mouth
Disequilibrium (dizzyness)
Excited behaviour
Fish involuntarily rise to the surface
Fish are afraid of light (photophobia)
Fish are easy to catch by hands
Fish are inert
Fish breathair from the surface of the water (swalling air)
Fish do not react to anything
Fish do not take food very well (low appetite)
Fish do quick spinning movements
Fish do swinging movements
Fish feed well, but are skinny
Fish go to vertical position
Fish hang near the surface
Fish hang near the surface with heads up
Fish hide in secluded places
Fish itch (fish scratch on the rocks and other objects)
Fish jump out of the water
Fish lie at the bottom of the tank with mouths wide open and spread their fins and gill covers
Fish lie at the bottom on one side
Fish lie on the gravel
Fish move in violent rushes
Fish stay near the surface or air stream, but not take air
Fish stays in corners of a tank tilting body down
Fish stop feeding
Fish swim belly-up (upside down)
Fish swing on their side
Gill covers are tightly closed after death
Gregarious fish stay separated one by one
High sensitivity to mechanical irritants
Laboured breathing
Rapid breathing
Trembling fins

Other symptoms

Bloody faeces
Gill arches displacement
Rotten egg smell
Slimy faeces
Threadlike faeces
Water has a milky appearance
White, white-yellow, white-brown worm up to 5 mm in length seen on gravel or on the glass when light is suddenly turned on

Lab analysis (microscopic observation)

Symptoms listed below is impossible to obtain without special devices such as microscope. If you don't have such equipment do not mark any of the symptoms below.

A microorganism (bacteria) is seen with 400x magnification

A protoazan Trichodina which uses a ring of hooks to hold onto the fish

An autopsy of a severely affected fish reveals a mass of yellowish-brown nodules, the size of a millet seed, which can be seen with the naked eye and which cover the surface of the viscera. Microscopic examination will reveal cysts in the affected organ
An autopsy of relatively big fish shows blood froth coming from blood vessels
An autopsy reveals inflammation of the intestines
An autopsy reveals numerous nodules in the spleen, liver, kidney, heart, intestines, gills, muscles, sex glands, skin, eyes, and the skeleton. The nodules have a curdled consistency and are of brown or white color

An autopsy reveals that mucous membranes are inflamed, with a large number of bleeding sports
An autopsy reveals viscera covered in fat and blood lighter in color

An autopsy reveals white nodules on the affected organs (connective and muscular tissues, the walls of the intestine, kidneys, liver, gills, genitals, and cornea). The nodules are filled with egg-shaped cysts of Gluges, 3.5-5.9 micrometers
Ciliated parasite is seen on the skin and gills of sea water fish Brooklynella hostilis

Degeneration of liver
Flagellates 8-15 micrometers large of different form which depends on the relative position to the observer. There are two flagella on the front part of the organism Ichthyobodo necatrix Costia necatrix

Liver injury
Microscopic examination of gill filaments reveals fungal hyphae and spores. Fungal hyphae are tree-like, 2660 microns in width. Hyphae are nonseptate, which is an important diagnostic feature, they contain gray spores, 813 micron in diameter
Microscopic examination of gills and gill arches slime shows parasites Dactylogyrus

Microscopic examination of skin and fins scrape shows parasites

Microscopic examination of skin and gill slime shows the parasites

Microscopic examination of skin and gills scrape shows rotating ciliated infusoria

Microscopic examination of the intestines and gallbladder show the Hexamita (Octomitus) truttae flagellar parasites. They are teardrop-shaped, 10-12 micrometers long, with 4 pair of flagella in front of it and 1 behind.
Microscopic examination shows lymphocystic cells resembling eggs of tapeworms and crustaceans. Lymphocysts can be observed on the walls of the stomach, spleen or ovaries as well as in the gill cavity, between gill filaments

Microscopic examination shows bacteria

Motile protozoa are observed with a magnifying glass

Protozoan Tetrahymena

Sucking parasite Gyrodactylus with elongated body (0.2 0.8 mm) and has at its posterior portion a sucker with two central large hooks, surrounded by sixteen smaller hooks for attaching to a host

There are attached parasitic crustaceans on the fish body

There are white-gray nodules in the muscle tissue. The spores of parasite are seen via microscope

Through the magnifying glass it can be observed that scales have small goldish bumps on their edges, which can turn into continuous coating in bad cases

Whitish worm several millimeters in length is seen with naked eye

With magnification of 40x a ciliate protozoan can be seen under the skin and epithelium outgrowth on the mucous tissue

Data field below are not required, but it would be nice of you to fill them in.

Any remark:

If you find this tool usefull, please, consider supporting it by small donation: paypal.me/artemkuchin