6 Signs of A Happy and Healthy Fish

What are the signs of a happy and healthy fish, both freshwater and saltwater? As a good keeper, understanding the signs and body language of your fish is very important to ensuring that you keep it safe. Having a pet fish is nature’s best gift. Keeping eyes on signs of fish healthy and happy is our responsibility.

When it comes to petting, stay extra alert about your creatures’ health. Especially when it comes to petting a fish, be extra alert with it. A fish cannot reciprocate about its health. 

Cute Reptiles as Pets

6 Signs Of Healthy Fish(And yes they Happy)

A happy and healthy fish doesn’t have white spots or blemishes on its body, doesn’t have fins that are torn or ragged, doesn’t have bulging eyes, spine never bends or gasps for breath and gills are never inflamed or red. All fish, irrespective of the species, have similar healthy behaviors and signs and you can easily tell when something is wrong with them through some odd behaviors.

The health of your fish can be determined through their gestures. Look at these 6 signs to identify the health of your fish:

  • Nice Appearance Glow

Now, let’s explore what are those exactly mean!

Nice appearance Glow

Signs Of A Happy And Healthy Fish
A healthy freshwater fish

The health of a fish can be determined through its appearance. For instance, a healthy goldfish has a glow in its body. It has a shiny body with smooth scales all over the body. The change of color is quite common in goldfish. If you treat your goldfish with antibiotics it can turn fatal. 

  • A healthy fish spine never bends or gasps for breath. 
  • Gills are never inflamed or red. 
  • The body has a healthy color without any rough patches. 
  • Eyes are never bulged out. 
  • The scales are spotless and protrude from the body.
  • There are no holes, ulcers, or protrusions on the body. 
  • Eyes are bright and beautiful with zero signs of discharge or clouding. 
  • The body has color uniformity and does not have any discoloration or redness. 
  • Fins are always straight and intact with zero spots of white and grey. 
  • Fins are never ragged and torn and never clamp to the body’s sides. 

Causes of Rashes On Fish Skin 

Rashes On Fish Skin 
  • Fish has faced a physical injury. 
  • It has fungal infections like Saprolegnia, Branchiomyces, and Fusarium.
  • Has Fish Pox: Fish herpes virus is quite common in Koi fish. 

If you find white, red, or grey patches on your fish skin then go and seek fish veterinarian doctor’s help immediately. 

Your Fish Eats Well

Fish ich
Fish ich

Apart from the oxygen in the water, your fish requires food to live. A healthy fish has a healthy appetite and it enjoys eating its food. 

  • A fish taking two to three meals in a day is fine. If your fish’s appetite is good then ensure you schedule your feedings. 
  • Fish change their eating habits with age, a young fish demands more food. The desire to eat food decreases with age. If your fish is aging and then it’s appetite might decrease. 

How to Identify How Much Your Fish Eats

Every fish has a different appetite. If your fish eats in a day or two it is completely normal.

For a new fish, you need to observe and understand it’s appetite. If your fish stops eating as per its schedule then something is wrong.

If you cannot identify then check its swollen belly. Sometimes swollen belly can be a sign of a disease or a problem. If your fish is not eating, seek fish veteran’s help immediately. 

Engage In Activities With Ease

Everyone loves seeing their fish healthy, happy, and active. When a fish is active it engages with other fish in the aquarium. A healthy fish normally tends to jump and play around with others

Fish Engagement Activities To Identify It’s Healthy and Happy

  • A healthy fish never lolls at the tank’s bottom. It enjoys and tries to be playful with other mates inside the aquarium. 
  • It swims easily and effortlessly. Fins of an active fish are whole open. The open fins allow it to swim through whenever needed. 

Reason For  A Fish To Circle At The Tank’s Bottom:

Unclean water is the reason for a fish to dart at the tank’s bottom. Ensure the water is clean.

Unclean water is the reason for a fish to dart at the tank’s bottom

Unhealthy water can be a reason for a fish to fall sick. Make sure to equip the aquarium with a water filter. Prefer changing 25% of the tank’s water every two weeks or so. 

Measures to Be Taking While Changing Tank’s Water

Most of the fish illnesses happen due to water contamination. Gills only stop working when there is a lack of oxygen in the water. 

  • Refill your tank with water having room-temperature. 
  • Ensure the tank’s water filter is working well. 
  • Remove chlorine from the water before adding it to the tank. 
  • Test the water for high ammonia or nitrate levels. 
  • Check if the water has enough oxygen for your fish. Use an air stone in the tank for oxygenation. 
  • Check pH and saltwater levels.

Measures To Be Taken When Activity Levels of A Fish Decreases 

One of the signs of not healthy fish is stop moving
One of the signs of an unhealthy fish is stopping to move
  • Keep a check on the water temperature. A fish cannot survive under too hot or too cold temperature.   
  • The temperature of the water should remain constant throughout the day.
  • If you add tropical fish to the tank, use a heater or thermometer. 
  • Do not keep the heater in the goldfish and other coldwater fish’ tank.

Exhibiting Standard Fish Behaviour

Just like humans, every fish behaves differently. Some are active and move in schools while others prefer staying alone. If your fish enjoys schooling with other fish it is completely normal. 

How Would I Know If My Fish Is Behaving Abnormally

  • Usually enjoys its me-time but suddenly starts interacting with others.
  • It generally moves around with other fish but now stays isolated.

Make sure to have details about your fish, its behavior, and its mood. A sudden change in fish behavior could be due to health deterioration. 

Breathes Normally

We all know fish breathe through the gills. The gills of a fish rise and fall rhythmically when it breathes normally.  To identify fish health, check its breathing pattern. 

Normal Breathing patterns of a Fish

  • Ensure fish expands its gills regularly, not rapidly. 
  • Opens and closes gills completely, neither too fast, nor too slow. 
  • A fish’s breathing pattern changes as they age, do not worry.

Abnormal Breathing Patterns Of a Fish  

  • Fish gulping at the surface is a sign of less oxygen. A goldfish appears at the surface only when the oxygen level is low.  

Impedes Usual Spaces in Aquarium

Just like humans, fish have special resting places inside the aquarium. If your fish enjoys staying at its isolated spot then do not worry. 

Signs When a Fish is Sick 

  • Not adhering to its normal pattern and has left its favorite spot. 
  • A bubbling treasure chest suddenly starts sinking to the tank’s bottom, Example: a goldfish never swims at the surface. If your goldfish grasps at the surface then the situation can be alarming. 

Is My catfish Sick As It Swims Upside Down: 

Some catfish normally swim upside down. If your catfish roam to the sides of the aquarium then do not worry.  

Steps To Follow While Introducing Fish to New Tank

  • Fish should be first kept in a quarantined area
  • Initially keep the fish bag into the tank in which fish was brought. 
  • Keep adding some tank water to the bag after every 15 minutes
  • Use net after an hour to pick and place in the tank. 
  • Avoid dropping your fish to the tank. Always use a net, and allow your fish to swim through the aquarium. 
  • In the initial days observe if the fish is settling well or not. If the fish behaves normally even after days then it has adjusted well. 

Some Other Reason For a Fish Falling Sick

Besides of the signs of healthy fish above, there are a few other signs that you can look at.

Fish need 10-12 hours of light daily to stay healthy and happy.  Ensure you expose your fish to enough light in a day. Add a light timer to the aquarium to give fish enough light they need.


How do you know if a fish is healthy?

When trying to tell if your fish is healthy, these are the things to check and ensure that none is acting weird. Eating regularly, breathing properly, clear and bright eyes, active and swimming energetically, and good fins.

How do i know if my fish are happy

It’s easy to know or differentiate between a healthy and happy fish from a sick and abnormal fish. They usually swim back and forth freely and energetically around the tank, fast like humans, breathe normally, do not appear fearful and have a vibrant glow to their skin.

How do I know if my fish is sleeping?

Generally, a fish that is sleeping would lie motionless, often at the bottom of the tank or near the surface of the water. Sleeping fish are usually slow to respond to stimulus or things going on around them. Also, if you watch their gills carefully, you’ll notice that they’re breathing at a very slow pace/rate.


To ensure your fish is healthy, you need to feed them proper diet and clean their tank regularly.

Another concern from us is that overfeeding will not good for your fish. Ensure you know how much do your pet fishes eat and how often to feed them. You can use an automatic fish feeder to help you with that.

But, before using any automatic feeder, make sure you know their basic diet.


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