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How to Calm Down Stressed Fish

fish in aquarium

It can be difficult to notice when our pets are in distress, especially because they can’t tell us exactly what’s wrong. For aquatic life, this can be even more challenging, as can knowing what to do once a problem has been recognized. The truth is, even small, subtle changes in fish behavior or appearance can indicate stress. It’s important to know how fish become stressed and how to react quickly when it happens.

Why fish get stressed

Anyone who has fish knows that they are complicated creatures. Like humans, they get stressed but in ways you might not have considered. Some of the most common fish stressors include:

Poor water quality or incorrect water temperature: Besides the actual water that you put into your aquarium, water quality is impacted by a number of other factors, including the filter system (and whether it’s working properly), the accessories and décor in the habitat (gravel, aquatic plants and other objects), the food you feed your fish and even your fish itself. Different species of fish also require different water temperatures throughout the day. Without clean, properly maintained water, fish can easily become stressed.

Moving to a new aquarium: Fish are extremely susceptible to stress due to changes in their environment. This is why cleanings—and especially making the move to an entirely new aquarium—should be done carefully and properly. Speak with a Petco aquatics specialist before you move your fish to a new aquarium to ensure you’re following the best procedure to avoid as much stress as possible for your fish.

Overcrowding: Not all fish are compatible and, even when they are, each one requires a certain amount of space in order to happily live and grow. Adding fish to an aquarium also increases the waste output, which may necessitate updates to filtration and additional cleaning procedures. 

Lack of aquarium décor: While overcrowding an aquarium isn’t a good idea, neither is leaving it completely empty. The type of substrate you use is important (gravel and stone, for example, help provide a surface for good bacteria to colonize, which helps keep nitrogen levels in check), while real plants help stabilize nitrogen and CO2 levels. Adding décor for your fish to hide in and swim around is not only fun for them but often helps reduce stress in the aquarium, as long as you remember to clean it regularly.

Improper diet: Your fish require a species-specific diet. The proper diet will help your fish live a long and healthy life, while an incorrect one may leave your pet lacking needed nutrients. Food remnants can also affect water quality and cause an aquarium to become dirty when excess food is not removed after feeding and buildup occurs between cleanings; making an effort not to overfeed your tank can help prevent these problems.

Illness or injury: A fish who is suffering in some other way—like from an illness or injury—will likely have some additional stress side effects as well.

How to calm down stressed fish

If you notice that your fish is breathing heavily or gasping for air, or if you pick up on any behavioral (reduced activity, excessive hiding, sporadic movements or decreased appetite), physical (nicks or tears) or color changes (lighter to darker, darker to lighter, discoloration or spots), they could be suffering from stress.

Before you can determine how to best help them, you’ll need to try to troubleshoot the cause. Run through the items above to determine if any of those factors have recently changed.

Depending on the changes that may have recently taken place, you can try:

  • Using a water quality test kit to ensure your habitat is at optimal pH, nitrate and ammonia levels for your fish’s species. You can also bring a sample of water into your local Petco where someone can test it for you.
  • Checking that the filtration system is operating properly.
  • Examining your fish’s skin and fins for fading colors (which could indicate skin or gill flukes) or small white specks (which could indicate Ich).
  • Trying a stress coat product, which can help remove chlorine, neutralize chloramines and detoxify heavy metals to set up optimal water conditions. It can also help heal skin wounds and torn fins.
  • Reducing overcrowding by moving additional fish to a new tank, or getting a larger aquarium.
  • Provide additional oxygen to your tank by ensuring there is enough surface area of the water exposure to air, by using a waterfall, air pump or adding live plants. 

If you think your fish may be stressed, speak to an aquatics specialist who may be able to help diagnose the issue and help you find a solution.