Things You'll Need
- Aquarium Air Pumps
- Aquarium Filters
- Aquarium Filtration Supplies
- Aquarium Fish Nets
- Aquarium Heaters
- Aquarium Lights
- Aquarium Thermometers
- Aquarium Water Conditioners
- Saltwater Test Kits
- Freshwater Water Test Kits
- Tropical Fish
Instructions
See if any foreign object has fallen into the tank.
Check for dead animals in the tank. If you find one, remove it immediately and inspect it carefully for signs of illness.
Check the tank temperature. Heat can kill fish in a hurry. Sudden changes in temperature - especially cooling - can prompt an infection.
Check the pumps and tubing. Ensure that aeration is adequate.
See if the filters are clogged. Be sure the filter media is clean and doesn't need to be replaced. Cloudy water is a sure sign that there's a problem.
Be sure the fish are adequately fed. Very hungry fish will take bites of other fish in the tank. Also beware of overfeeding, which can change ammonia and nitrite levels radically.
Watch for fish with poor appetites. This could be due to competition from more dominant fish, a new environment, a parasitic infection or inappropriate food.
Check the fish for red or bleeding gills, and note whether a fish is gasping for air at the surface. In these situations, suspect ammonia poisoning, which has no cure. It's common in new and full tanks and causes permanent damage to the gills.
Do a chemical test. Check ammonia and nitrite levels, as well as pH levels. Water quality is the culprit in many fish illnesses. Low pH and ammonia or nitrite poisoning will cause dark coloring in fish, an increase in skin mucus, erratic swimming and gasping for air.
Watch for abnormal behavior such as odd swimming patterns, refusing to eat, hiding more than usual, sluggishness or extreme aggression.
Notice darting in normally sedate fish, which indicates water quality problems, skin parasites or stray voltage from faulty equipment.
Check for head standing, lying flat, floating upside down or sideways and poorly coordinated swimming. These are symptoms of either a swim bladder infection or an intestinal obstruction. These problems are caused by overfeeding or by eating dry food too quickly.
Check for darker coloration in fish, which can indicate chemical imbalances in the water, parasites or bacterial infections.