Lighting guide for your goldfish tank
Choosing appropriate lighting system for your goldfish aquarium can be quite a daunting task. There are several different types to choose from and as well as various bulb combinations too.
When choosing a goldfish aquarium lighting system the biggest deciding factor is whether you wish to keep plants in the tank with the goldfish.
If the answer is no, then the most cost effective route is to stick with standard T-8 fluorescent fixtures and globes. These are the same ones you see lighting office buildings and stores. They are dirt cheap and provide adequate light to observe your goldfish.
You can buy these pretty cheap from any hardware store such as Bunnings.
If you want to keep plants in your goldfish aquarium however, you’ll need to explore either t-5HO, compact fluorescent or metal halide lighting.
T5HO
T5HO (the HO stands for high output) is probably the most readily available and is simply a thinner brighter version of the cheaper t8 tubes. They require their own fixtures and produce a high intensity of light per watt.
Don’t do what I did and stare at the tube when you first turn them on… unless you like being blinded for five minutes or so.
t5HO bulbs are apparently water resistant and come with special splash resistant covers for the ends of the tubes. Personally I don’t trust lights and water so I always run my cover glass between the fixtures and the water.
For maximum efficiency you are supposed to change the bulbs every 6-12 months but unless it’s noticeably dimmer or you are running a co2 high tech setup I wouldn’t bother unless the bulb blows.
Compact Fluorescent
Compact fluorescent lighting is essentially a t5 tube but bent into a curved shape so as to save space. Think of them as a bigger version of the compact fluroescent light globes you can buy for your home fixtures.
Compact fluorescent tubes can be a little bit harder to find stock of, for example I was unable to find tubes locally for a t5 compact fluorescent fixture even at hardware stores. I did however eventually find an Australian dealer online who had stock but by that time I’d moved on to a t5HO setup.
The tubes are also available to fit different fixtures, there is a square fitting (square pin) and a round rectangle fitting (straight pin), so make sure you buy the appropriate tubes for your particular fixture.
If you can find the tubes though they are slightly cheaper then a t5HO setup although the tubes have a noticeably shorter life span.
Compact fluorescent fixtures generally come with a splash proof piece of perspex at the bottom of the fixture to protect the globes. This is important to check for though if you are buying a non-aquarium specific fixture.
It is also worth nothing that for smaller tanks a standard household lamp fitting can be used provided adequate wattage is applied to the tank size. This can be a very cheap DIY option for people with smaller tanks.
Metal Halide
Metal Halide isn’t something I’d personally worry about in a goldfish tank. The initial outlay is a lot, the light intensity is massive overkill and the bulbs are expensive and have comparatively short lifespans.
Not to mention that the bulbs don’t like water and have a tendency to explode from precipitation!
Personally I run two Hagen T5HO fixtures, a single and a double with 2 Life-GLO t5ho tubes total. Originally I had two in the twin unit but decided it was too much light and was promoting algae growth so I dropped down to 2.
Lighting fixtures
Whichever lighting system you decide to go for, the lighting system should be solid and non-corrosive. Even behind a perspex cover as well as your tank cover glass water is going to find it’s way into the lighting system and the last thing you want is a nasty rusty looking fixture.
Construction of the fixture should be sturdy with enough room for ventilation of heat produced by the tube. You don’t need heaps of space but so long as the tube isn’t ridiculously close to the reflector inside the fixture you should be right.
One final thing to look for is the inclusion of a splash proof cover along the bottom. This helps in maintaining the lighting tubes and is a safeguard against accidentally splashing a bit of water on the unit.
A guard is particularly important if you run an airpump with an airstone or bubblewand as the bubbles pop at the surface and splash water everywhere. You’d be quite surprised at how high splashes get from even the tiniest of bubbles.
Normal tank cover glass can be sufficient if your fixture does not have a splash cover but do make sure water isn’t splashing up from the edges of the cover glass.
Watts per gallon/litre
If you want to keep plants I’d advise to stick with low tech when it comes to goldfish. What this means is you should aim from anywhere from 0.25/1 watts per litre/gallon (wpl/wpg) to 0.5/2 wpl/wpg. 0.5/2 wpl/wpg is on the upper scale of low tech and should be suitable for moderate to high light plants, 0.25/1 wpl/wpg is fine for low light plants.
To work out the wpl of a lighting system for your tank, simply divide the total watt output of the lighting system by the litre or gallon volume of your tank.
If plants aren’t your thing then your free to decide aesthetically the level of light you wish to have in your tank. Light isn’t essential for goldfish and they won’t mind either way so don’t be afraid to go with ambient shades if that’s your thing.
When deciding on non-planted tank lighting, be aware that t5HO and compact fluorescent tubes are much more penetrating then t8 tubes. Whilst the cheapness of t8 might be appealing you might find you need to buy several additional tubes to match the same intensity you’d get from much fewer t5HO or compact fluorescent tubes.
Having run both I wholeheartedly believe the extra outlay of a t5HO system is worth it in the long term.
Lighting timers
Any goldfish lighting system should be run on a timer. Light timers can be expensive from supermarkets but they are pretty dirt cheap at hardware stores such as Bunnings. I bought two $5 cheapies about a year ago and both of mine are silent and still going strong. The only noise they make is a click when the lights go on or off.
One thing to remember with timers is that if there’s a power out they lose their ‘clock’ and might need to be readjusted to the correct time. This just involves rotating the dial till it’s at the correct time and only takes a few seconds.
Digital timers are available but in my opinion the price difference isn’t worth it.
Lighting duration
Once you’ve got a light timer the next question is how to long to leave the lights on for. Again the answer is determined on whether or not you choose to keep live plants in your goldfish tank.
Without live plants you can leave the lights off until the evening so that you can still view the fish at night. If you are home during the day there’s nothing wrong with having the lights on either as well as into the evening.
Do allow the goldfish enough time to sleep though as they do benefit from 6-8 hours of complete darkness like the rest of us!
If you are running plants a good starting point is 10-12 hours per day. If algae shows to be a problem you can reduce the hours and reduce the lighting intensity (wpg/lpg) accordingly.
I work during the day and don’t need to see the fish in the morning so I set my light timer to come on at 12pm midday and turn off at 10pm at night. That way when I get home I can enjoy the goldfish all evening and they wind up going to bed roughly the same time I do.
The most important factor is matching your lighting system to your tanks needs. This took me a few months to get right so don’t be too discouraged if you find it frustrating at times, especially if you’re trying to keep plants alive! Remember that any changes you make might take a few weeks for any changes to become apparent which can also be a tad frustrating.
Once you’ve got it right though lighting is pretty much a maintenance free ‘set and forget’ component of your goldfish aquarium and a pretty important one at that. I mean who doesn’t want to stare at their beautiful goldfish all day long?
December 22nd, 2011 at 4:47 pm Ashley(Quote)
I have a two gallon goldfish tank with a fluorescent type light but instead of a bar thingy it has
Like little teeny bulbs. Theyre like dots. It changes color from white to blue.
I just any to know if it’s okay to leave it on all day. Please reply with a helpful answer! Thx!
December 22nd, 2011 at 9:35 pm ozsoapbox(Quote)
Sure they’re not LEDs?
Safe to leave on all day either way, I assume they run cold.