Ammonia Poisoning

Symptoms

Spotting illness early gives the best chance of a cure, so check your fish daily at feeding time. Gasping at the surface, red or inflamed gills, lethargy, loss of appetite, and fish hovering near the filter outlet. Often strikes in new or overstocked tanks. If you see several of these signs together, act promptly rather than waiting.

Causes

Caused by ammonia building up in the water from an uncycled filter, overstocking, overfeeding or a dead fish. Ammonia is highly toxic even at low levels. In nearly every case the underlying trigger is stress, poor water quality, or the introduction of an infected fish - all of which weaken a fish's natural defences.

Treatment

Do an immediate large water change with dechlorinated water, stop feeding, and use an ammonia-detoxifying conditioner. Add beneficial bacteria and reduce stock if needed. Test daily until ammonia reads zero.

While treating, increase aeration, remove activated carbon from the filter (it absorbs medication), finish the full course even after the fish looks better, and keep the water immaculate with regular changes. Always dose for the tank's true water volume and follow the product instructions.

Prevention

Always cycle a tank before adding fish, never overstock or overfeed, and keep up regular water changes and testing. The golden rules are simple: quarantine every new fish for 2-4 weeks, never overstock or overfeed, avoid sudden temperature or chemistry swings, and do regular partial water changes. A stable, clean, low-stress aquarium prevents the large majority of disease.

FAQ

This information is general guidance, not veterinary advice. Consult an aquatic vet for serious cases.