I've noticed a few of my malawis do it, seems mainly the Melanochromis tho (I think only them actually). But they'll do almost like a barrel roll at the bottom of the tank, like swimming on their side for about half a second. I don't think it's an illness, it seems quite purposeful, and they don't do often, but I do see 'em every now and again.

What are they doing and why?

my fish do it sometimes too, I think they are scraping algea off rocks or something?

my fryeri & yellow labs do that too, i think its either trying to show off or something similar. I have only noticed my males doing it

My Johanni male does this and I have noticed he only does it when he is trying to entice a female into his pit for spawning..

I have also noticed fish doin this alot when the Nitrates are getting higher Also noticed that it settles down after a water change

Test your water when you see them doing it and see if that shows up anything

Brad

they just have an itch.. :lol:

I have also noticed fish doin this alot when the Nitrates are getting higher Also noticed that it settles down after a water change

Test your water when you see them doing it and see if that shows up anything

Brad

Hehe. Don't think it's that. They were doing it after my water change too, not too long ago. I try and change 20% every week.

All three of my Female Albino Kribensis do it all the time.

It is a very good possibilty its from Nitrates

Check your water and let me know what the readings are

I have tanks where they get a weekly water change and they still show high Nitrates

Nitrate build ups arent always from lack of water changes

Brad

Yeap as above as Brad said can be a strong possibility.

However in my case with the Johanni male it has been a breeding dominance behaviour. He is the only one to do it and it has been always when he has been busy pit digging and in breeding mode. But that is my case and may not possibly be the case with other peoples fish... definately never hurts to test your water, better to be safe than sorry

i had a post about it a while ago. http://www.fnzas.org.nz/fishroom/kribensis-scratching-themselves-on-gravel-vt20367.html

yep nitrates (I should know mine are off the chart ) .

Will do the test, now that I think of it, I think it's only been my male Melanochromis'. They don't seem to touch the gravel sand when they do it tho.

They swim up and down on their side in like a wave like motion.

yep nitrates (I should know mine are off the chart ) .

now that, in a democratic society, we have decided its nitrates that the reason behind it, what are they actually doing? I have seen mine do it very close up as they are in a tank right behind the couch so i sit literally am a few inches away. when i seen it happen they dont seem to actually scrape their bodies on the substrate. their fin gets close but not totally sure it actually touches the substrate either.

now that, in a democratic society, we have decided its nitrates that the reason behind it, what are they actually doing? I have seen mine do it very close up as they are in a tank right behind the couch so i sit literally am a few inches away. when i seen it happen they dont seem to actually scrape their bodies on the substrate. their fin gets close but not totally sure it actually touches the substrate either.

That's what mine do, they don't touch the gravel sand, just go on their side and swiftly go in a wave like motion almost up and down for a split second.