Harlequin rasbora issues

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Caol Ila
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Harlequin rasbora issues

Post by Caol Ila »

About four months ago, I picked up some harlequin rasboras from an LFS and immediately upon getting them home and into my 240L tank, noticed that one looked off and appeared to have something that looked like cotton wool disease. I took it straight back to the shop. Others all seemed fine, released into tank, all well, and I wrote it off as a netting injury or dodgy fish. Then in mid-December, I noticed another rasbora with fuzzy white growths on its side. I caught it and put it on a quarantine tank. It was the smallest one and I wondered if it had been injured, perhaps by one of the raphael catfish (I'd just bought a second raphael for the tank). Treated it with anti-fungal stuff and it looked better, so it went back into the main tank. Sadly, it died the next day. A week ago, I found another rasbora with cotton wool-looking stuff on the base of its tail. Meanwhile, all the other species in the tank are absolutely fine, and I have some sensitive fish in there when it comes to water quality, like corys and rummy nose tetras. Water parameters test fine -- ammonia, nitrites, nitrates all at 0, and PH circa 6.6. I do 30-50% water changes every week.

What could be going on that's only affecting rasboras? Could it be just a weak stock of rasboras with some kind of underlying issue? I don't know if it's the right thing, but currently all the rasboras are now in the quarantine tank, being treated with Waterlife myxazin.

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RedLee
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Re: Harlequin rasbora issues

Post by RedLee »

I haven't got any answers for you on this but it sounds like what happened to one of my Hets before Christmas.
White fluffy growth around the tail. Sadly, its tail fell off and the fish died.
I didn't treat with anything and from then until now, the other Hets look fine.

Hope you get it sorted. :)

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Re: Harlequin rasbora issues

Post by plankton »

Sorry for your losses. :(
It certainly sounds as though they came in with a problem.
That's relatively unusual for harlequins, but I expect it's something to do with how (and where) they are farmed.
What you're doing sounds about right.

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Re: Harlequin rasbora issues

Post by Martinspuddle »

I remember seeing something on the internet a long time ago about Harlequin Rasboras being found to have cotton growths and the affected fish have rapid breathing. Part of the conclusion was bad husbandry while being in dealers shops, I wasn't surprised to be honest.

All aquarium fish can be effected by this problem though poor hygiene, i.e. dealers not sterilising nets between aquariums and very poor water quality, not the first or last time over the years I have come across dealers who don't change their water from one week to another!

Treatments, I found aquarium salt bath can work well, antifungal treatments or in serious cases specific antibiotic formulations from a veterinarian are effective in treating cotton wool disease.
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Re: Harlequin rasbora issues

Post by Pleco Fan »

When you are doing your water changes you could always add something like Seachem Prime.

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Re: Harlequin rasbora issues

Post by WinterRose73 »

So that's what it is... I haven't had it for a long time but I had problems with it with a group of black phantoms (my first fish). Even though I took pictures and spoke to three LFSs no one really seemed to know what it was.

I think I got told to treat it with either melafix or primafix (can't remember which does what off hand).

But useful for future ref to know what it was.
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Re: Harlequin rasbora issues

Post by Caol Ila »

Here's an update. A round of Waterlife Myxazin had no effect on the fish. Then I tried Praziquantel in case it was a parasite thing. Nothing. As per advice on another forum, I treated with aquarium salt and daily water changes. Again, nothing. I tried one more round of Myxazin to no avail. By this time, the rasboras had been in the hospital tank for a month. The good news is that six that were fine continued to be fine, showing no signs of fungal infection or any other pathology. The bad news is that the poorly one started to look worse, turning pallid in colour, gasping, struggling to swim. I decided to call it a day. The heathy ones were reintroduced to the main tank, and I euthed the unwell one with clove oil. On post mortem examination, I saw that a deep lesion had formed at the base of its tail, where the initial fungus had been, which explained why it wasn't swimming very well. It reassured me that I made the right call in terms of putting the fish down, but I'm left wondering why none of the treatments worked. Guess it's one of those things.

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Re: Harlequin rasbora issues

Post by Ric »

Thanks for the update. Its always good to hear how things pan out a little while later, even if none of the treatments had worked.

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Re: Harlequin rasbora issues

Post by Gingerlove05 »

Sorry for your loss :(
Sounds like you did everything you could for them

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Re: Harlequin rasbora issues

Post by Caol Ila »

Balls. As of this morning, another one of the rasboras has white lesions on it. Back into quarantine they go. Any ideas?

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