Dust Particles From Gravel

[Kaidonni]

My current tank has been up and running for 5 1/2 years now, however I still suck dust out of the gravel when I do a deep gravel vacuum. October/November last year I noticed the Clown Loach was doing quite a bit more flashing than he used to, and since then have been constantly checking water parameters; for those who aren't aware of my current situation, reading my earlier thread - http/www.fishforums.net/index.php?/topic/437154-dosing-prime-on-top-of-fish/ - should be able to clear a few things up (I'm in need of rehoming the Clown Loach, this tank is completely inadequate for him).
 
I do get minute levels of nitrite appear in Nutrafin liquid tests, and by minute I mean I have no idea where it'd come on the scale, it's nowhere near even 0.1ppm (it is quite faint, I have to compare against a sample of clear tap water to get the most out of the test). Not quite sure about ammonia as I was dosing with Prime every day until a few weeks ago, and Nutrafin tests will give false positives; I used up my old test kit so, using a recently newly purchased one, as best I can tell I have been finding it is identical to clear tap water (for the most part...swapping the test tubes around, it looks like there's some ever-so-faint colouration, but it might simply be the lighting for that to happen). Of course, he's not flashing at the moment, so I don't think the Prime stopped it (I did at first).
 
He did have some markings on his body back in early October, a number of whitish/greyish marks, and they didn't match Ich, Velvet, or any other known disease as far as I can tell. I think they're gone, haven't noticed them since (but I might not be looking close enough), so I assume they may have been scratches. His gills look slightly dark around the edge, but I can't tell if it's natural colouration or not (they've been like that for months and months now). He acts relatively normally under the circumstances, sometimes darts when I get too close and move around. He did appear to be shimmying last Friday, I tested water parameters and nothing was different; he's appeared fine since then. He might be underweight, it's difficult to tell (and I've stressed over the threat of chronic wasting).
 
My main question is...could the flashing I noticed last year have been caused by dust disturbed during a gravel vacuum? I never saw any signs of parasites, and it's now four months later (which is a long time). I now only perform a vacuum once a week (not the same day as the filter is cleaned), and while trying to do it thoroughly, not as deep as I used to unless I plan to completely remove the remaining dust from a section of gravel.
 
I try to provide as much information as possible since I'm rather paranoid and worried these days, and if I miss something important or I'm misinterpreting something...

 

[Kaidonni]

As you might have guessed, I've been worrying again tonight. New thoughts always occur to me, and now I'm thinking on the stunting the Clown Loach will have suffered - there's a castle I've kept in the tank for years, and it was in there when the other two Clown Loaches were around, so it was more of a squeeze back then.
 
He hides in it, but he only just fits if he lies on the gravel, and he has to turn to leave the castle. I've been worrying how much leaving the castle in even now has harmed him, and if I should seek an alternative. I can't just remove it and not replace it (and removing it might harm the biological cycle due to the beneficial bacteria on its surface). The stunting is likely irreversible, but I fear making it even worse. The ideal situation is that he is rehomed shortly in the new few months, so is it even worth it replacing it? It's basically closing the stable door after the horse has bolted...

 

[Munroco]

you can put something else in for him to chill in, and take the castle out if he decides his new cave is better.

 

[Kaidonni]

Thank you for the reply. I've been looking at some alternatives that Star4 made me aware of this morning, although they are slate and I do have a few concerns about that (reading up online doesn't make those concerns disappear).
 
Anyone anything to add on the dust particles issue?

 

[Kaidonni]

I should probably expand on my last post. I've been looking at this, and wondered what precautions I should be taking if I were to put a slate cave into the tank?

 

[Byron]

I'll respond to the several issues raised, beginning with the dust from the gravel.  This is harmless.  I never completely clean new sand or gravel, and the dirt is not going to harm fish.
 
On the shelter, this is mandatory for loaches; they must have a good hiding place, or they will be highly stressed.  My favourite is Malaysian Driftwood, as some of the chunks have tunnels and crevices that suit loaches admirably.  PVC pipe or the slate decor linked are other options.  I always favour natural, but just have more than one.  Loaches like to select their "home."
 
The flashing can be caused by several different things.  Ich is one, which first attacks fish in the gills, hence the flashing before any spots will be visible elsewhere.  And clown loaches are highly susceptible to ich  There are other parasites including gill flukes (reddened gills usually with flashing), and internal protozoan.  High levels of ammonia or nitrite (above zero), or nitrate (keep this below 20 ppm, preferably no higher than 10ppm).  Almost any water issue can cause flashing, as these irritate the gills.  Sometimes food gets stuck, I have seen this in corys who sift the sand for food and the sand gets pushed out the gills, and sometimes a bloodworm with it; you would probably see this clear enough.
 
But don't assume something and start medications; these usually do more harm, and they certainly add more stress, so you should be very certain of the issue before resorting to medications.  Obviously, water changes will not harm, and sometimes this is all it takes.  But being aware of the issues in your other thread, I wouldn't overdo them here.
 
Byron.