Drifting harlequin rasbora

[palaeodave]

Hello. I've got a school of Trigonostigma heteromorpha who are very lovely little fish. I started out with 12 but I'm now down to eight. I've found no corpses (such is life with a tank full of loaches and japonica shrimp) but I have noticed a bit of 'drifting' from one or two of them. They're swimming along, apparently in perfect health, then all of a sudden they freeze and start drifting, usually sinking and turning upside down as they go until they end up in the path of the powerhead or hit something. Then they spring back to life and swim off as if nothing had happened. I can't see any difference between them when they aren't drifting. There are no other external signs.

What do I do?

[loachmom]

I have harlequins, and, yes, they are lovely fish. When I first bought 8 of them, I treated them with salt and levamisole to rid them of parasites. I lost 4 of them almost immediately. Then I had this one that did just what you are describing. Exactly like that. It looked perfectly healthy externally, but it did this drifting and swimming upside down thing.

I started to think that maybe it was osmotic shock. Then I remembered that I had never put the carbon back in the tank after the levamisole treatment. I wondered if the levamisole was becoming toxic. So I added carbon, and the fish completely recovered in about two days. I'm not sure if that was the cure or not, and I don't know why the other three fish were unaffected. All four fish are doing great, and I added another to the tank later.

Well, enough of my rambling. This may not have anything at all to do with your problem.
Hope your fish recovers.

[Diana]

loachmom may be on to something: Add activated carbon to the filter (or change it if you run it there regularly- put some fresh stuff in there), it will remove a long list of things. Who knows if this will cure the fish, or what actually happened with her fish, but it is worth a try!

[palaeodave]

I never have carbon in my filter but we just so happen to have a new bag of carbon left over from a while back when Lee was treating his tank for...don't even remember now. Might have been algae. Anyway, I'll put that in.

This brings me to another question (and I suppose I should really start a new thread for this) - how often do people clean the hoses of their external filters? I've had mine (Eheim Pro 2028) just over a year now and the outlet pipes have a coating of nastiness in them and if I ever turn off the filter then turn it back on again, some of it comes out. Chunks of the pinkish (could just be because I have an aqua-glo) nastiness can only be described as 'meaty'. My guess would be diatoms....

[loachmom]

What!! You haven't cleaned your filter hoses in over a year! Forty lashes for you!!

Just kidding! I've only cleaned mine once since I've had it, and that's been more than a year, at least. I get that same debris shooting out of my spraybar when I turn the filter back on after a cleaning. I guess I'll wait to see what answers you get.

I really did hate cleaning those hoses.
If I was really rich, I'd just buy new ones.

[palaeodave]

Heh yeah, buying new ones would be great. But I just spent waaaaaaaaay more than I had planned up at Emma's shop on the weekend so fish spending is going to have to wait until the next installment of my research grant!

How did you go about cleaning yours?

[andyroo]

Long bottle brush or wire/string with cotton-bud in the middle. Or remove and let dry then rinse. Or turn the system off, bang the hose with a spoon then turn it back on again.
The dark and stinky algae that grows inside seems very tasty, according to my fish.
A

[palaeodave]

Cheers Mr Roo. I may have to scrub out though as we seem to have different stuff growing inside our pipes. Mine is a pinkish colour and I don't think it's algae. My fish have never eaten it that I've seen.

[loachmom]

To clean mine I took a sturdy cord that was quite a bit longer than the hose I wanted to clean. I cut this in half and attached a piece of plastic scrubbie in the middle. Then I used a shopvac to suck the one end of the cord through the hose. After that, the process of pulling the piece of scrubbie back and forth through the hose began. I did this in a mop sink so I could keep running water through the hose to keep rinsing the gunk out.

[palaeodave]

Then I used a shopvac

Qué? Atlantic divide....

[loachmom]

Then I used a shopvac

Qué? Atlantic divide....

Sorry about that.

It's a strong vacuum cleaner used in garages and workshops. It pulls the cord through nicely. A regular vac might work just as well. My husband learned to do this in his job. He attaches a plastic shopping bag to the end of a cord to pull wires and such through very long stretches of pipe. The shopvac sucks the plastic bag and cord right through.

[palaeodave]

Then I used a shopvac

Qué? Atlantic divide....

Sorry about that.

It's a strong vacuum cleaner used in garages and workshops. It pulls the cord through nicely. A regular vac might work just as well. My husband learned to do this in his job. He attaches a plastic shopping bag to the end of a cord to pull wires and such through very long stretches of pipe. The shopvac sucks the plastic bag and cord right through.

That's ingenious!

[palaeodave]

Well, I'm down to 7 now. The one that was drifting was looking in a bad way last night. It seemed unable to raise its dorsal fin and I swear I caught a glimpse of what might be velvet on it, although there's no sign of that today on any of the fish. Switched off the lights just in case.

[loachmom]

Sorry that you lost the fish. Hope you don't lose any more of them.