Whilst you wouldn’t want to keep your guppies in permanent darkness, they don’t need an aquarium light as such. Providing the aquarium they live in receives some light, either natural light from a window or ambient light from the room the aquarium is in, the guppies will be fine.
Guppies are colorful, easy-going, and hardy. They will thrive in just about any aquarium setup we give them. I got my first guppy 30 years ago and I have been keeping and breeding them ever since.
What Are The Benefits Of Having A Light On A Guppy Tank?
Whilst the guppies themselves don’t need a light, there are a number of benefits to keeping them in an aquarium that has a light.
Guppies do really well when kept in aquariums with real plants.
Real plants not only give the aquarium a natural feel, but they also help keep the water in good condition. Live plants absorb both ammonia (fish waste) and nitrate (again, from fish waste) and help keep the aquarium water ‘sweet’. I keep live plants in all my guppy tanks.
Live aquarium plants require around 8 to 10 hours of light a day to grow. Having a light on the aquarium is essential when there are live plants.
A day/night cycle
Having a light on the aquarium helps maintain a day and night cycle which in turn helps keep your guppies healthy by allowing them time to rest at night. Guppies live their lives at full speed.
During the day they eat, swim, and try to breed constantly. Having a time when there is no light gives them a period when they can ‘sleep’.
A light allows us, fish keepers, to better observe the aquarium
The fish in the aquarium are totally reliant on us as fishkeepers for their everyday needs. To be able to properly check on your guppies each day, a light on the aquarium really helps.
With the aquarium properly illuminated, we can see right to the back and into the corners. Also, what is the point of having bright, active, and colorful fish if we keep them in a poorly lit aquarium?
A light helps algae grow
Helps algae grow? But algae is bad, right? Contrary to popular belief, algae is one of the most beneficial things you can have in your aquarium. Algae help remove harmful fish waste from the water. Algae also provide a source of food for many fish, especially guppies and guppy fry.
See my article Do Guppies Eat Algae for more information.
Whilst we are aquarists who spend so much time trying to remove algae, we should really be encouraging it. Having a light on the aquarium can actually help reduce fish waste!
Downsides Of Not Having A Light
When you have an aquarium without a light, observing your guppies behavior can be tricky.
It can be harder to see if a guppy is being bullied by another fish. It can also be harder to spot the early signs of pests or diseases. In the early stages, Ich (whitespot), can be tricky to spot. Your guppy may only have one or two small spots on it. In a dimly lit tank, you may not notice them.
By the time the spots are obvious, your fish may be covered in them and they may have spread to the other inhabitants.
Low light levels also make spotting things like dead or dying fish harder. If a large female guppy was to die in your aquarium, but you don’t notice due to there not being any light, the decaying body can have a detrimental effect on your water quality.
An ammonia spike caused by the decaying body could cause more fish to die. A domino effect could lead to you losing all your fish.
Does The Type Of Light Matter?
Guppies themselves do not care what sort of light you have on your aquarium. I have kept guppies in aquariums lit by very expensive Fluval 3.0 lights and by cheap ‘normal’ light bulbs from Walmart. The source of light matters less than the length of time the light is on.
Ideally, an aquarium light should run for about 8 to 10 hours each day. Having an aquarium light attached to a timer means the aquarium will receive the same amount of light each day.
Check out an article I wrote recently titled Does The Fluval Aquasky Grow Plants
Guppies themselves do not need light as such. Having a light on an aquarium just makes life easier for us fish keepers. A light makes observing your aquarium easier and means you can grow live aquarium plants, which in turn creates a better environment for your fish.