fishy behavior

Question
Hello,

I've recently setup a 30gal freshwater tank, filtered by a Fluval 205.  It's just begun to cycle w/ NH3 = 0.5ppm, NO2 = 0ppm, still.  I have 3 Gymnocorymbus ternetzi (black skirt tetras). There are plenty of (plastic) plants in the water, some wide leaf, some grassy, and a large rock with holes for them to hide in.

My question is:  I have a 19watt full spectrum fluorescent light over the tank and the fish have recently begun a bizarre behavioral change.  When we first introduced them to the tank, no matter whether the light was on or off, they went about their business throughout the tank.

But, recently they have begun a new ritual.  Whenever the light turns on, they immediately break formation and dart for the nearest hiding spot(s).  To see if "we" were just crazy in thinking this, my wife and I turned the tank light on, and off, then back on again.  Sure enough... each time the light turned off, the fish IMMEDIATELY came out from their hiding spots.  Back on, they do the hide and seek drill.

They refuse to eat when the light is on... but will eat without any problem when it's off.  

I know the habitat for this species calls for subdued lighting... but is this really normal?  they didn't do this before... and they certainly don't do it in the fish store.  Last thought on this: by increasing the school size once the tank is cycled, might they feel more confident in a larger school and be (more) oblivious to the light?

One last question:  what UPPER tolerances to ammonia and nitrite does this species have?  I know the temp and pH ranges... but not much info have I found on the web for NH3 and N02 other than keep it close to zero ppm.  Your thoughts?

Answer
Hi Tad. Boy I had to laugh at this one. I thought somehow you got my tetras!!  If you added "shimmies" to your list it would be my tetras exactly!  Mine did this when I moved them from a 55 gallon to a 20 gallon (5 of them). Same thing.  All of a sudden they were FREAKING when I turned on the light.  And the weird thing is, it stopped as quickly as it started! What I did was (because they were starting to fade in color and everything from stress because of the light)....I turned the light on every day for a short amount of time and gradually increased it.  Use your own judgment.  I would start with 10-15 mins at a time, depending on how they are acting.  Increase every couplle of days (as soon as they settle down from the new length of time).  THIS worked for me. Of course, I cannot promise you because that's all I had to do and I never could find anything online too much about it.  I cannot even give you a good answer on if you increase the # of them, they may still do it.  They are just neurotic little guys who need some "conditioning" sometimes. Just my opinion though.  If you've just started cycling, you may want to be careful about adding more fish before it's fully cycled. You may throw things off enough to do some real damage. If things are staying in check, keep with that (in my opinion, again).  

As far as ammonia, you want to keep it as low as possible through the spike, and you'll do this with partial water changes.  I would suggest that you get a freshwater master water test kit that contains the important tests: ammonia, nitrites, nitrates and PH (High & Low). And you can get GH and KH test kits too, as they are important. On those tests, they give you all the info you need. You ideally want to keep the ammonia "in the yellow", and you can do this through water changes (or at least in the pea-green/yellow area). I would suggest that you buy something called "Prime" and use that FOREVER as a water conditioner. Prime makes ammonia, nitrites and nitrates less lethal. And it doesn't mask the readings. Just makes it less poisonous.  It won't replace partial water changes and tank cleaning, but assists it.

For more info check this link out:  http://www.americanaquariumproducts.com/Nitrogen_Cycle.html

Feel free to get back to me if you have any other questions.  Good luck! (And remember, it's "take your time" that gets you where you want to go!!

Good luck!