Fish Health Problem Guide

Fish repeatedly spits out food or makes gulping motions without eating.

Fish darts erratically or rubs its body against surfaces (flashing), suggesting external irritants.

Fish repeatedly gulps at the water surface, indicating oxygen deprivation or gill damage.

Fish spends unusually long periods concealed behind decor, plants, or substrate.

Fish repeatedly leaps toward the surface or out of an open tank.

Fish moves little or not at all, resting on the substrate or floating listlessly.

Fish refuses food for one or more days, ignoring offerings it normally accepts.

Gills moving much faster than normal; visible labored respiration.

Fish scratches itself on rocks, gravel, or decor repeatedly.

Fish attacks tank mates or owner's hand when previously calm, chasing or nipping.

Fish abdomen appears abnormally distended; scales may protrude outward (pinecone effect).

Fins are held tightly against the body instead of fanned out normally.

Fish spine appears bent, curved, or the body curls unnaturally.

Fish floats involuntarily at the surface, unable to descend normally.

Fish appears noticeably paler or less vibrant than usual.

Patches of scales are absent, exposing bare skin.

Fish color is washed out or significantly lighter than when healthy.

Fish sinks involuntarily and rests on the substrate, unable to rise.

Fish appears severely thin with a concave abdomen despite regular feeding.

Fish tilts or rolls on its side while swimming, cannot maintain upright orientation.

Fin edges appear shredded, torn, or uneven without obvious injury.

Dark or black patches appearing on the body, fins, or skin.

One or both eyes protrude dramatically from their sockets.

Eyes appear opaque, milky, or covered in a white film.

Fish body coated in thick, slimy, or whitish mucus layer beyond normal slime coat.

Fin edges deteriorate progressively, often with a discolored or ragged border.

Cotton-like white or grey fungal growth on body, mouth, or fins.

Hemorrhagic red streaks or blotches visible under skin or on fins.

Pin-point or larger spots, velvet dust, or discoloration appearing on fin tissue.

Small white salt-grain-like spots covering the body and fins — classic sign of Ichthyophthirius multifiliis.