Do Goldfish Need Sunlight? (Describe The Benefits!)

Do Goldfish Need Sunlight

If you want to pet a goldfish, you need to be acquainted with the care requirements of goldfish.

Are you curious to know that goldfish need sunlight? If you set up your tank outdoors, you must ensure sunlight exposure to keep your goldfish healthy. 

In this article, you will learn how sunlight is beneficial for goldfish.

Do Goldfish Need Sunlight?

The answer is yes. Goldfish need adequate sunlight to stay healthy and active. Mainly, sunlight causes the goldfish to have vibrant colors. In addition, it provides valuable vitamin D to keep your goldfish strong. It is also necessary for the tank plants to grow efficiently and helps to grow algae. 

Make sure to provide enough sunlight to your goldfish.

See the picture of the tank in natural sunlight-

How To Set Up a Goldfish Tank Outdoors?

Generally, goldfish live in ponds and shallow lakes where they can get sunlight easily. However, they are not adapted to low light conditions, so you must ensure the light for your goldfish’s health.

How To Set Up a Goldfish Tank Outdoors?

You can keep your goldfish in an indoor room where they can get natural sunlight easily.

What you’ll need-

  • Tank
  • Decorations
  • Water
  • Aeration 
  • Heater
  • Water change

Setting up process –

Step 1: Select a tank

Select a large tank if you are setting up a goldfish tank outdoors. Usually, goldfish need a 30 gallons tank at least and you have to add 10 gallons per goldfish.

So, choose a large tank to have the sunlight properly. Make sure to keep the surface of the goldfish tank open for an accessible entrance to sunlight. But try to have indirect sunlight exposure for the welfare of the goldfish.

Step 2: Add some decorations

Make sure to put gravel, some plants, and hiding places to make the tank look natural. 

You can use plants, and the ray of sunlight will help the plants to grow well. Next, add some hiding places for goldfish. If there is too much heat from the sun, the goldfish can hide in any hiding place.

Step 3: Add clean water

To keep healthy goldfish,  you need to add clear water. Before adding water, make sure to cycle the tank.

It is a goldfish tank, and goldfish create a lot of waste and ammonia. So, it would help if you cycled the tank to consume ammonia levels.

Step 4: Ensure aeration 

Make sure to provide aeration to ensure oxygen. In addition, the aeration system should be robust. 

Aeration makes the goldfish active, which causes fast digestion and grows the goldfish quickly.

So, make sure to generate adequate oxygen. If the aeration system is not done correctly, it might strain the goldfish.

Step 5: Use a heater

Use a heater to warm the water if the temperature goes down. Goldfish are cold-water fish and they are exposed to sunlight. Despite this, use the heater as it operates automatically.

Warm water can’t harm the goldfish and moves slowly to a low temperature. So, add a heater to the outdoor tank of the goldfish.

The warm water makes the goldfish active and it causes fast digestion to grow fast.

Step 6: Change the water

Change the 30% to 70% tank water weekly to remove the dirt. Make sure not to change the 100% water.

How Much Sunlight Does Your Goldfish Need?

Your goldfish needs 13 hours of sunlight to make them active, healthy, and colorful. So try to provide sunlight indirectly to produce fewer algae.

Goldfish expose themselves to sunlight. Therefore, you can keep your goldfish from 7 am to 12 pm or 1 pm under sunlight.

What Are the Benefits of Sunlight for Goldfish?

What Are the Benefits of Sunlight for Goldfish?

Goldfish can survive without sunlight, but it is helpful for them. 


Sunlight helps to make the goldfish colorful. However, goldfish can remain colorful under any artificial light. 

Without any light, the goldfish will lose its color and fade. After fading, they look paler, and sometimes it even causes death.

Natural life cycle

Sunlight helps keep the goldfish’s natural life cycle as it gets natural light throughout the day.

Thus, your goldfish will get a natural life cycle under the sunlight.

Vitamin D

Animals need vitamin D to strengthen their bones, and the sunlight is the source of vitamin D. So, keeping your goldfish in the outdoor tank will help the fish get vitamin D easily.

Grows Algae

Sunlight helps to grow algae quickly that may turn into microorganisms which is helpful for fish and fries.

The algae can be overgrown if the sunlight is robust and lengthy. 

Can Goldfish Live in the Dark?

You can’t keep goldfish in darkness. But, they can use their sense of smell to move in the dark.

If the goldfish remains in darkness for a long time, it may slow down their body pigments. Goldfish are diurnal fish, so they need light to stay healthy.

Do Goldfish Need Light at Night?

Goldfish need darkness at night to sleep. As diurnal fish, they sleep at night. It needs a calm environment, so darkness is necessary for sleeping. 

Goldfish don’t have eyelids in their eyes, so they sleep by opening their eyes. 

Light at night can hamper sleeping, which may develop stress in the goldfish.

Is It Possible for Goldfish To Survive Without Sunlight?

Goldfish can survive without sunlight. However, light is necessary for the coloration of goldfish. Therefore, ensure to provide artificial light instead of sunlight to stop the loss of coloration.

If they fade, they become pale, and that leads to death.

Do Goldfish Need UV Light?

Goldfish don’t need UV light though it is a natural part of sunlight. UV light is not used for color pigmentation.

UV light generally kills microorganisms in the tank, and direct UV light can burn the goldfish’s skin.

Can Goldfish Live Without an Air Pump With Full Sunlight?

If you keep a tank outdoors where goldfish can get direct sunlight, you don’t need any air pump to produce oxygen. 

How To Care for Your Goldfish?

  1. Enough space for moving
  2. Feed sufficient foods
  3. Ensure to have the oxygen properly
  4. Maintain the temperature 
  5. Provide adequate lighting for color brightening
  6. Keep the water clear
  7. Add compatible tank mates


If you still do not understand do goldfish need sunlight, describe the benefits! Then in this article, you will discover the facts–

  • Goldfish need adequate sunlight to stay healthy and active. 
  • Mainly, sunlight causes the goldfish to have vibrant colors. 
  • In addition, it provides helpful vitamin D to keep your goldfish hard. 
  • It is also necessary for the tank plants to grow and algae growth happens with sunlight. 

Moreover, now you know how sunlight is beneficial to goldfish and what is the alternative option for this.

Frequently Asked Questions

Q1. Do Your Goldfish Like Led Lights?

Goldfish like LED lights, and it is suitable for goldfish. It is a permanent lighting system for goldfish tanks. LED light provides an orange and red glow on the goldfish’s body.

Q2. How Can You Tell That Your Goldfish Is Unhappy?

You can consider your goldfish is unhappy by seeing the following sign–

  • When their swimming pattern is strange
  • It feels lethargy
  • It sits at the bottom of the tank
  • Lack of appetite 

Q3. What Do Your Goldfish Do All Day?

Goldfish swim around the tank to explore, play with tank mates, eat food, and sleep at night.

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