Is my aquarium light to bright?

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Jason the Lost

Aquarium Advice Activist
Joined
Aug 16, 2005
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Chicago
I have a 20 gallon FW non planted tank. The light right now is the stock 15w light that came with the hood, it seems kind of bright. My Black Phantom Tetras seem to really hate it as they hide behind things while its on yet as soon as I turn it off they dart right out literally and start swimming around the rest of the tank. They will stay in the same cove behind a driftwood structure and some plants the entire time the light is on and as soon as its off its playtime.

1. Is there a different type of light I can get for the tank that will be less jarring for the tetras? Maybe not so bright?
2. I'm thinking of getting one of those artificial floating philodendrums (sp?) to filter some of the light and also give them someplace to hide besides the back of the tank...they are like 4' long though, seems like it might be excessive for a 20 gallon even if its curled up.

Any suggestions?
 
that is the usual amount of light for that size tank. Your fish will become accustomed to it and act normally with time. Fish are often startled when it clicks on. One way to avoid this is to have a room light go on a half hour before the tank light. You can even do the reverse to provide a smooth transition to darkness. Sometimes fish hide because of the presence of people in the room, and with the lights out they feel more secure.
 
That's actually very low light. I generally have three to four times as much on my tanks. Fish do need decorations such as caves, driftwood, or plants(plastic or real) to hide behind so they'll feel safe. Once they settle into a tank and know they can hide if needed they start swimming around in the open more. You could get a different color of bulb. For my brightest tank I have purplish plant lights that come on first because they don't seem as bright and then the full spectrum white lights. In the evening the blue lights come on and then the main lights go off. Light in the red or blue spectrum isn't as easily visible by people so it seems dimmer and is why lights used in the home are mostly yellow and green spectrum light. The problem with different spectrum lights is everything in the tank will look colored :lol:
 
The light that you have is stock lighting for a 10 gal tank. I don't think it's too bright. They could just be shy. How many are in the tank? You may want to increase the number and see if they act more "normal".
 
there are 5...the light just seems bright i guess in perspective to every other tank i see. most tanks seem to have a more subdued lighting where mine looks like the fish are getting ready for a vegas review.
 
Your wattage is what is stock. My 10 gals both have 15 Watt bulbs. The reason why it looks so bright is because the tank is not very tall. Therefore the light reaches the bottom of the tank without problems. When you get into the larger tanks that have 1.5 Watts per gal, they are taller. Therefore the light doesn't reach the bottom of the tank as much. Is the tank cycled? If it is, you could try adding 1 or 2 more tetras.
 
also try adding taller plants that go to the top of the water to help shade parts of the tank, fake or real...but if you want real try a Melon Sword i have had lots of success with them and they are fast growers in low light

HTH
 
I think less than 1wpg is a bit low for a melon sword. You might be able to grow some floating plants. That would also help with water quality. Duckweed is extremely easy but considered a pest by many for how hardy and fast growing it is. Not a problem if you're willing to just scoop a cupful out every so often and it shouldn't be hard to find at all. Hornwort is great at sucking up nitrates and grows into long strands that will make a plant ball at the top of the tank. However if it gets too big or you try to plant it in such low light the lower shaded parts will fall apart and you'll have needles everywhere. Floating plants would also not care about the substrate in the tank or need root tabs.
 
I bought a "Sun-glo" brand light of the same wattage. Its much better...its a more subdued natural looking light than the beaming white flourescent that came with the tank hood.
 
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