Do goldfish need light?

Do goldfish need light?Do goldfish need light? Well, how would you like to be kept in the dark?!

Goldfish definitely do need light! Like most animals, goldfish would not be healthy if permanently kept in dull or dark conditions.

Unlike some fish that live deep in the sea, wild goldfish live in lakes and rivers that are often illuminated by relatively bright daylight. The lighting conditions in your aquarium should replicate this natural environment as closely as possible.

What happens if I don’t give my goldfish enough light?

If your goldfish tank is kept in a place that does not have enough light then you may notice your fish’s color start to fade. Goldfish have even been known to turn an unhealthy white color when not getting the light they need!

Changes in light levels also let your goldfish know whether it’s currently day or night. A lack of light – and therefore a lack of a day and night cycle – will affect how well your goldfish sleeps, how much they eat, and even their temperament and behavior.

Can goldfish have too much light?

While it is important to make sure that your goldfish gets enough light… you also have to make sure they don’t get too much light!

You should never place a goldfish tank in direct sunlight. The water could get too hot and the strong light will encourage the growth of algae, which will cloud your water.

Also, just like too little light could confuse your goldfish into thinking it’s always night time, too much light will make your goldfish think it’s always day time, and that will throw off their sleeping, eating and behavior just as badly.

Do I need an aquarium light for my goldfish tank?

If your tank is in a poorly lit area – or if you want to grow live plants – then it would be a good idea to include a light in the hood of your aquarium.

If you do add a light to your aquarium then switch it off at night to replicate natural day/night cycles. Like humans, goldfish prefer to sleep in the dark.

Read more in our Goldfish Care series.

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  • kris hopper

    I read that you recommend that gold fish should only be with other goldfish. my question is what about betta and sucker fish? would they be okay with goldfish?

    • TheGoldfishTank

      We wouldn’t recommend it. There’s a chance that bettas and goldfish could fight or harass each other, and bettas prefer slightly warmer water than is suitable for goldfish.

      We wouldn’t recommend sucker fish either, as they can actually suck on the goldfish! That causes damage to the goldfish’s slime coating and creates sores which could before infected.


    • Joseph Azzopardi

      No, they are tropical fish (prefer warmer water temperatures) unlike goldfish which is a cold water fish.

  • rumtopf

    Even Hillstream loaches aren’t all that compatible. They require cold water, yes, but they also need that water to be very fast moving, highly oxygenated with a rocky “stream bed” substrate. A specialised hillstream loach tank would be long, shallow and very overfiltered to simulate a rushing stream. Goldfish are pool fish and wouldn’t deal well with the turbulence that hillstream loaches require. People still keep them together under goldfish friendly conditions, of course, but it’s totally not ideal for the loaches.

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