What kind of light bulb would you recommend for a fish only 20 gallon long freshwater fish tank?

Thanks

LED , they make spectrum correct ones for tanks , or a flourecent with the correct spectrum.

Thanks

Need more information.

What type of plants (if any) will you have in the tank?

What type of Livestock (if any) will you have in the tank?

also

What is your budget?

I can recommend a 600$ fixture if you want it to be a nano reef with finicky corals, or I can recommend a 10$ t8 if its going to have a goldfish and gravel in it.

Edit:

Just saw Fish only, get a t8 flourescent hood.

Although they make cheap low PAR LED hoods as well:

http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3733+23542&pcatid=23542&r=949

Dammit. I thought this thread was about "Fish Tank Lightning". That might have convinced me to get another fish tank.

I got back into it recently. Buy a nano tank. I got a 12 gallon reef setup now. Sooo much easier than 10 years ago. One weekly five gallon water change.

Full spectrum LED or fluorescent.

Go SW

yup

This would just be for keeping baitfish after fishing trips or other little fish like that

I have some aquatic moss as well but that is about it in terms of plants.

I could just use plastic plants if I really needed them

I've got the 8 and am getting the 29 very soon......fucking love them.

Ultimately depends on what you are wanting to accomplish.  I like growing freshwater plants - depending on the plant they can take rather high lighting (not unlike coral - but different parts of the spectrum).  In the past people generally used florescent for fish only tanks.  Incandescent put off too much heat.  If you wanted to grow something, you used LOTS of florescent tubes, or used metal halide.  Metal Halide puts off a TON of heat, can be very efficient as well (florescent tubes are not very efficient due to the nature of the tube and reflectors).  Point source lighting makes reflectors work better and adds a shimmer to your water.
Somewhere along the way T12 tubes died, and were replaced by T8 (T6, then T5).  Ultimately while T8s are still used in some setups - most people went to pc (power compact - essentially U shaped T5's), while a few went to spirals.  Now the hot new trend is LED's.
LED's have tons of advantages - but they are new tec and carry a premium.  Individual emitters are point source - so they get a much larger % of their light to the water.  Their spectrum can be custom designed (and does not waste electricity on IR and UV like MH lights do.  Recall the Metal Halide lights run VERY hot - like 400-500 degrees hot).  They do share the advantage (abet at the cost of some shimmer) of tending to be in arrays, so they can provide even light without being pulled away from the water - being close to the water also adds efficiency.
Put simply.  I have run 250 watts of MH, 196 watts of PC, 200+ watts of T8 on the same tank at different times.  I am about to try 28 watts of led's.  The MH looked incredible.  The over driven t-8 got great growth, pc's worked fine as well.  If you can wait till Monday I will post some before and after pictures of the MH and the LED.  I am doing it because the MH is failing again and I am tired of buying damn expensive bulbs (MH bulbs run $60, pc bulbs run $40+ (I use 2 - so $80 a change), and the T8's were cheep, but that fixture caught on fire (water not electrical cause).



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There is a lot to study about spectrum.  But one thing to keep in mind is PAR and another is the Ra, and then there is K.  Par is light intensity.  It replaced the old watts per gallon rules.  Technically it should useful spectrum light intensity.  Ra - this is something photographers deal with.  How close to natural light does the light work.  Noon sunlight is 100.  a Ra of 60 will not look as natural as one of 90 - that said, the spectrum might be less good for growth.  In the past LED makers would screw with the spectrum to make lights look bright (targeting green, we see green real well) - but they did not look natural.  K tends to be a way to describe visible tint.  Get below 3500k and it will be a warm tint.  Get to 10k and it will be a cool blue - 20k is going to be very blue (but might be natural looking for some reefs as only the blue spectrum penetrates 30' in nature, all the reds are filtered out.
fwiw, Finnex Fugeray has good reviews on Plantedtank.net for low light (which is still quite bright compared to walmart aquarium lights) - while the Ray 2 is better for high light plants.  Prices are dropping on leds - but med-ligh light for my 50 gallon is still running me $150 (but then again a mh system is often closer to $400-600).











This was my tank right after I replanted it 3 weeks ago - that is 250 watts of metal Halide  - notice the amount of shadows the plants created.





A small pic of the full system in it's old glory - the light is a pendent, underneath is c02 and a canister filter in the crock. - all the electronics are underneath the bench top (with a really neat mounted powerstrip with individual switched outlets).
 

That is what I have. A single strip and reflector for an 17-18 inch light tube

FWIW you may want to look into these guys MH bulbs http://www.lightexports.com/servlet/the-Aquarium-Lighting/Categories I know a couple people who swear by them and a local store running them over the frag tanks, along with a few guys on a couple reef forums. I just ordered 2 bulbs from them yesterday to try out as I'm going back to halides over my reef. Not sure if their other types of bulbs are any good I'm sticking with my guissmans and ati's for t5's.

Nice planted tank btw, I just run 2 T5's over mine but nothing high tech just fert dosing and mostly medium light plants.

Thanks for the link.  I was very annoyed back when I took the picture about the price of bulbs.  I have found cheaper sources since then.  The only problem is the bulb life has not gotten any better and has continued to deteriorate.  My last 2 bulbs have lasted several weeks before I started having problems.  I have changed both the sockets and the ballasts and still have the problem.  The current bulb is not dead yet - and I have 2 spares in box.  I am going to clean out the ballast to make sure the new problem is not an overheating issue in the ballast box.  Then I will do a test run of the light plugged directly into the outlet (bypassing any current/voltage issues that the timer, extra cords, or power strip might be causing).  After that the last possibility I see is that the fixture itself is causing a thermal issue.
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The Finnex Ray II light is on my tank now - it is NOT nearly as bright as my metal halide (my camera used a 1/20 exposure on it versus a 1/129 exposure on the MH).  It looks slightly brighter than a single 2x odno shop light (I used to run 2 of those).  It is a much more ascetically pleasing package.   The spectrum might be more efficient as well - but that is hard to tell without time.  I am going to try it for a bit as I really do not have time to manage a EI dosed high tech tank anymore.  Plant growth is insane when one of those is running smoothly - I was pruning gallons of plants weekly.
If I do decide the Ray II is not enough (and replace it with something brighter) - I have a 30 breeder (also 36") I can put it on and use as a grow out tank.






Ray II






HQI MH
Oh,  back to the OP - one light I am considering toying with are some 120volt LED flood lights off of ebay - keep the 5-7k.  10watts for about $15 or so.  A couple hanging above the tank would be fairly attractive, and give a point source ripple effect.