Here are the answers to the questions we get asked the most about keeping fish. You’ll be an expert in no time!
- What happens if an aquarium filter doesn’t run continuously?
If an aquarium filter doesn’t run continuously, several issues can arise:
- Water quality declines: Filters remove harmful waste, toxins, and debris. When off, these substances build up quickly, harming fish health.
- Oxygen levels drop: Filters often help circulate water and promote oxygen exchange at the surface. Without continuous flow, oxygen levels may decrease.
- Ammonia and nitrite spikes: Without constant filtration, toxic ammonia and nitrite can accumulate, stressing or even killing fish.
- Algae growth: Stagnant water encourages excessive algae, which can cloud the tank and disrupt the ecosystem.
For most aquariums, especially those with many fish, keeping the filter running 24/7 is essential for maintaining a healthy environment.
- How to Handle Your Aquarium When You’re on Vacation?
Prepare the Aquarium Ahead of Time
- Perform a partial water change and clean the tank a day or two before leaving.
- Remove any leftover food and debris to keep water quality stable.
- Ensure all equipment like filters, heaters, and air pumps are working properly.
Manage Feeding
- Avoid overfeeding before you leave; most fish can go several days without food.
- Use an automatic feeder to provide regular meals if you’ll be away for more than a couple of days.
Control Lighting
- Set aquarium lights on a timer to maintain a consistent day-night cycle and reduce stress for your fish.
Arrange Care Assistance
- For longer trips, ask a trusted friend or pet sitter to check on your aquarium. Provide clear instructions on feeding and equipment care.
Check Temperature Settings
- Make sure your heater is functioning correctly and set to the appropriate temperature for your fish species.
- What happens if an aquarium air pump or filter doesn’t run continuously?
If the aquarium air pump is not running continuously, oxygen levels in the water can drop, especially in tanks without sufficient surface agitation or plant life. This can stress fish and other aquatic creatures, potentially leading to breathing difficulties or even death.
However, in some well-planted or heavily filtered aquariums, continuous air pumping may not be necessary because plants produce oxygen during the day. Still, for most tanks, especially those with high fish loads, keeping the air pump running consistently helps maintain proper oxygen levels and water circulation.
- What happens if aquarium lights run continuously?
Running aquarium lights continuously—24 hours a day—can cause several problems. Prolonged lighting encourages excessive algae growth, which can cloud the water and harm plants and fish. It also disrupts the natural day-night cycle that fish and plants rely on, potentially causing stress to your fish and affecting their behavior and health.
To keep your aquarium healthy, it’s best to provide a regular lighting schedule that mimics natural daylight, typically 8 to 12 hours of light per day. Using a timer can help maintain this consistent cycle easily.
- Do aquarium fish sleep, and if so, how?
Fish are fascinating creatures with unique ways of sleeping. Unlike humans, fish don’t have eyelids, so they don’t close their eyes when they rest. Instead, they enter a restful state where their metabolism slows down and activity decreases. This period of rest is essential for conserving energy and allowing their bodies to heal and grow.
Different species have different sleeping habits. For example, bettas and angelfish often seek out quiet, sheltered spots behind plants or decorations. Meanwhile, clownfish and wrasses may bury themselves in the sand or hide in crevices to rest safely.
- What is the right amount of food for my fish?
Feed your fish only as much as they can eat within 2–3 minutes (in an established aquarium), typically two to three times a day. Remove any uneaten food promptly to prevent waste buildup, which can harm water quality and be toxic to your fish.
For more details, see our article Feeding Your Fish.
- What should I do when a fish dies?
We do not recommend flushing fish or other livestock down the toilet. Instead, please wrap them in a paper towel and dispose of them in the trash bin.
- Should I isolate a sick fish from the aquarium?
n most cases, removing fish from their familiar environment can do more harm than good. A separate tank often has different water conditions, filtration, and temperature, which can cause unnecessary stress and make recovery more difficult.
If you’re worried that your sick fish is being bullied by tankmates, consider using a large floating fry net to gently separate it while you treat the underlying issue in the main aquarium.
- Why is my fish trying to jump out of the tank?
Jumping or other erratic behavior is often a sign that your fish is stressed or uncomfortable. This can happen after being moved or disturbed, but it may also indicate poor water quality.
Use an aquarium test kit to check your water parameters and take the appropriate steps to correct any issues.
To identify the exact cause and find the best treatment, visit our Fish Doctor tool for a full diagnosis and expert guidance tailored to your tank.
- Why is my fish rubbing against the ornaments or Pebbles?
Flicking or scratching against decorations is often a sign of poor water quality. Use an aquarium water test kit to check the water parameters and take corrective action as needed.
In some cases, this behavior may indicate a parasitic infection. If parasites are the cause, you’ll usually see additional symptoms like small white spots (Ich) or visible parasites on the fish’s skin or fins.
To identify the exact issue and find the best treatment, visit our Fish Doctor tool for a diagnosis and tailored advice for your aquarium.