How much flashing/rubbing is normal?

[spiff44]

I haven't found this asked elsewhere and it seems to be elusive information... apparently some flashing/rubbing of fish is normal when there is nothing wrong. (based on several online fish diagnosis thread I have found) I don't quite believe this as if nothing is wrong they wouldn't be doing it. I understand that it could also be minor environmental triggers involved and I'm hoping that this is the case for me.

I see fish do it several times a night in the course of a couple hours of fish watching. This is out of a tank of several hundred fish. (1700gallons/7.0PH, light salinity .5%, 79degrees) They have been doing this for months but I haven't seen a fatality or any visual indicators of infection (no spots at all, white or black) and everything eats well. Ammonia and nitrites are at 0 and nitrates haven't went above .5%. The tank gets about a 20% a week water change when cleaning its two only filters, 2 ultima 4000 canisters. I do probably err on the side of over feeding to make sure everything gets fed, but it hasn't effected parameters so I think this is okay.

My main suspect is maybe rust in the water.. I dropped a couple wire clips into the tank and they disappeared into the rock pile where I couldn't get to them. I figured the would just rust away eventually.


Does anyone else see their fish do this on a regular basis with no seeming bad effects?

 

[spiff44]

Not sure why I'm bothering to follow up from the lack of replies..

Thinking it might be dechlor I was using wasn't getting rid of the chlormines in the water. Changed products and dosed the tank and it appears they might have stopped.

 

[Aquanero]

What type of fish are these? Is it one species or several? I've seen it in some schooling fish Tetras etc. but usually in cichlids it is caused by some type of external irritant.

 

[spiff44]

Its a community tank..its got some silver dollars...it was these that were flashing the most.. they have always done it.. but it also has a lot of different rainbow fish, tetras, barbs, mollies, platies and loaches. The clown loaches probably do it the 2nd most... I see them do it a couple times a week.

I'm more and more focusing on an environmental thing... I read that lots of plastic plants could be a reason too. I have a lot of plastic plants for aquariums, so I don't get this. If poly-chloride leaching was a problem from soft plastic you would think more people would have an issue with them. Every plastic aquarium plant i have ever seen is from the soft plastic they say to stay away from.

But before I start restructuring the tank I'm seeing if the chlormines are the issue. I was using an API water conditioner that I thought was highly concentrated. I based this on two doses marked on the bottle.. one for general dechlor use, the other to remove heavy metals. I always used the light dose but maybe it wasn't enough. I also thought that the sheer tank volume would dilute any residue chemical enough to give them time to dissipate. Maybe I was wrong. I'm using Chloram-ex now which is also highly concentrated and only gives one dose suggestion.

So now I"m doing a large water change a week and will see what happens for the next two weeks. I had previously did an arbitrary heat/salt treatment even though I never saw actual ich spots. It didn't make a difference.

 

[Aquanero]

Interesting. With Silver dollars flashing is normal as a way to signal danger, aggression, spawning like other tetras, as long as it's not excessive. Loches being for all practial purposes scaless do scrape up against things from time to time I noticed this with several species I have kept. Another posibilty could be and I'm reaching could be a stray current but it's good to eliminate all posibilties.

 

[spiff44]

That's good info too... I didn't know that about the silver dollars and might explain a lot, along with your general rubbing comment for the loaches. The flashing is never done excessively... just once out of the blue and they might not do it again all night. And they never do it hard enough to leave any marks or damage to their sides.

Well, I appreciate your reply and I wish more would as I would like to get a better feel for how normal this is. Now I'm starting to think I might be overreacting.