Today I saw a few of my fish brush themselves against some of the artificial plants I have in my 30 gallon tank. I have associated this in the past with possible bad water conditions irritating their gills. My water conditions seem fine:

Ammonia: 0
Nitrite: 0
Nitrate: 5

The water is crystal clear. The fish are very active and they all eat every drop of food I drop in the tank. Could there be some kind of problem? Or is it normal for them to do that from time to time?

5 gold barbs
3 rasboras
1 opaline gourami
1 bolivian ram

some fish do that from time to time...however it is not generally considered normal behavior.

Might I ask how large the tank is and what temperature it is?
Generally , rubbing against ornaments is called flashing. sometimes this can be a warning sign of diseases most likely ich. do your fish have any tiny white spots that look kind of like a sprinkling of salt. a common treatment is to increase the salt content of the water and raise the temperature incrementally about 1° a day until you reach the maximum temperature for the fish in your tank . Don't do this unless you see the white spots. if you have fish that are sensitive to salt then you may want to try a different route, there are a lot of medicines to treat ich. you think of any of the top of my head but I'm sure you'll have no trouble finding them. Take a look in the emergency forum you may be able to find some help there. take a special look at the pinned topics

This post has been edited by Torrean: Oct 7 2006, 11:39 PM

Ich was the first thing I thought of but none of the fish have white spots. Everything looks normal. It's a 30 gallon tank. Temperature is 78 degrees.

This post has been edited by HoosierInFL: Oct 7 2006, 11:49 PM

something I came across, that it may or may not be.

Gill Flukes (Dactylogyrus)

These tiny, worm-like flukes are barely visible to the naked eye. They infect the fish's gill membranes.

Things to look for

The gills move rapidly
The fish pants at the water surface
The gills are covered in mucus, and parts are eaten away
The fish may scrape itself against objects. (plants, rocks, ornaments)

Reference

Your & Your Aquarium, Author Dick Mills.

This post has been edited by Kiwigirl: Oct 8 2006, 11:40 AM

I posted about this problem on October 7th. It is now the 16th and the fish are still doing it. The tank parameters are still perfect. I do a partial water change each week. Still no sign of Ich. All the fish appear healthy and happy except for the scratching themselves part.

I'm at a loss with it. Any ideas?

Thanks.

30 gallon tank
7.2 ph
77 Degrees F
Ammonia 0
Nitrite 0
Nitrate 5

5 gold barbs
3 rasboras
1 opaline gourami
1 bolivian ram
1 algea eater

Fish do scratch from time to time, but if they are doing it a lot then something is irritating them.

It may well be a protozoan of some sort that is not easy to see (velvet, or smaller), or some unknown contaminant in your water

I would do a medium-large water change anyway, despite your parameters, give the fish some treat food (livefoods). Happy fish have strong immune systems and can generally fight off most things. Filter temporarily with carbon.

If the problem persists, add some salt, and raise the temperature, as previously recomended

look into itch...