Light intensity

[aerofish]

I have a 15 gallon new tank cycling. I have a few plants that the vendor claimed to be "easy" plants. But my fluorescent light is only 19 watt. Obviously I am far below the 2 watt/gal requirement. But the light seems pretty bright to me. I feel that if I put in a brighter light my future fish might be affected. Is this possible? What wattage should I put in there in order to maintain a well-planted (easy to medium plants only) tank?
Also, a question about cycling. I currently have only one zebra danio in the tank to aid in cycling. Should I add in more? and if so what type of fish are suitable for cycling?

 

[Bol]

Slightly more than 1 wpg is not bad for low-light plants, in my experience (in fact, it's pretty good in my opinion, as you're close to, but under, the point where you might be obligated to add CO2). But only low-light plants. I'd suggest doing some research first off, and identifying what your plants really are. Two places I'd suggest looking are Tropica's web site and PlantGeek's profile section.

I don't think stronger lights will bother your fish -- assuming you have caves and/or shady spots for the ones that don't really care for any type of light (cory cats, some loaches, etc).

By the way, light doesn't really "double". That is, if you double your lighting wattage, it won't really look "twice as bright" to the human eye, if you get what I mean.

Also, in my opinion, one zebra danio won't produce nearly enough ammonia to cycle your tank in a timely manner. I'd suggest six. If you don't care for danios, other "hardy" fish will work, too. Three platys, OR six or seven harlequin rasboras spring to mind as good cyclers.

 

[Silly me]

uhm harlequin rasboras is the worse cyclers in my mind.....next to rummy nose tetras

Lights, 19watts of what light

plant cant really use cool white lights, but these light does look bright to the human eye..

also fish swim in top of the water all there lifes in the full sun, you would turn red and peal like a union after a week,, so 5watts to the gallon is not going to do much.

I have 14watts over a 5gal betta tank the plant is just growing, but I have 100watts over a 36gal same lights same plants but in the 36, the plants is growing great.

 

[Lateral Line]

For fish cycling, I would stay away from tetras of any kind. I would also suggest Harlequins are not ideal. Most danios are relatively hardy in polluted tanks, as are many livebearers.

Zebras are probably the best bet.

 

[clutterydrawer]

By the way, light doesn't really "double". That is, if you double your lighting wattage, it won't really look "twice as bright" to the human eye, if you get what I mean.

would it to the fish's eyes though? would they be stressed if the light intensity suddenly doubled?