losing pygmaeus for no apparent reason, levamisole related?

[wijnands]

I'm stumped, baffled and sad actually because I'm losing corydoras pygmaeus.

May 2012 my daughter bought a group of six for her nano tank. About a year later she decided she wasn't taking proper care of her tank and we transfered the fish to my big tank. A few months later I lost one because something had bitten off his tail. I bought 2 new ones and everything seemed fine.

About 2 months ago I had a strong suspicion one of my T. Espei was suffering from an intestinal parasite. I bought some levamisole and treated the tank with this at 2mg/l after reading this http://www.loaches.com/disease-treatmen ... chloride-1
which seemed to do the trick.
The last 10 days I've lost at least three fish (and possibly more, my tank offers a lot of shelter and the pygmaeus also like to fourage in the densely planted parts of the tank. I've got another fish now who's rather pale and not very active.

Test results:
ammonia: 0
Nitrite: 0
Nitrate: often drops to 0 after which I dose to 5ppm to help my plants a bit. Highest level the last three months was 10.
Phosphate: 0.4ppm
Ph: 7.1
TDS: 125
Temp: 24c

Tank also contains 6 hatchets, 5 t. espei, 1 gold tetra, 15 green neons, 3 adult ancistrus claro and 4 fry. A thriving shrimp and MTS population. All of the other inhabitants are fine and act perfectly normal.


DSC_1340 by j_wijnands, on Flickr

I hope this is a complete enough story. I'm wondering if there's something in the levamisole treatment that is causing this. Anyone any ideas???

[JamesFish]

Hi,

I'm sorry your having trouble and know your an experienced keeper along with a few other things you contribute to.

Few minor queries the treatment I'm guessing you followed the guide and it lasted 3 rounds effectively. Is it possible they snuffled up the parasites mistaking them for food?

Also did they still have long as normal barbs & have you seen all your claro's lately I know a male ancsitrus is a brute on defending his eggs I cant see anything else in your list capable of ripping a tail off. I noted you had fry is it possible they are having a 2nd attempt?

I hope someone else here has used it and can help. Wish you and the fish all the best.

Edit - a small possible cause but long shot popped into my head perhaps they are building the medication in their bodies. Though I had is they pickup some with food as do other fish, they shuffle through debris that would include fish waste and may mistake any dead parasites found as food and so take an extra dose each time. That could possibly build up in their gut causing damage and possibly affecting food intake? It is a long shot as you were well below what levels some people where hitting the poor fish at.

[wijnands]

Thanks James.

I did a 2 course treatment doing my best to vacuum well the day after but never did see any dead parasites. It's perfectly possibly that there were some and they were eaten.
Barbs, as near as I can tell, are fine, the normal drooping mustache.
I don't think the ancistrus have anything to do with it at this time. Dad is under the tree to the right of the tank and clearly alone. The cories hideout is that mass of plants on the left where the ancistrus hardly ever go at bottom level.

[JamesFish]

Hi wijnands,

Had a reread of the link again sorry haven't had time to sit and study it yet but found it suggests it can stay for up to 90 days in the water.

For the benefit of anyone reading this thread later you might want to say about any big water changes done to attempt to dilute what's left in the tank if its causing the issue. I know the treatment says big water changes / vac after x hours of dosage time have you done any since?

If nothing else this might serve as a little bump for someone better placed to answer.

[CoryfanAad]

No chlorine Jeroen?? Maintenance of the watercompany ??

[wijnands]

@James: My regular schedule is a 25% weekly. After the treatments I did a 50% change so whatever's left is pretty diluted
@Aad: Doubt it. Latest lab results from the water company are the same as they always are. Besides I use mainly RO water and what little tapwater I use I run trough a brita filter first.

[CoryfanAad]

Okay !! That isn't the problem.

[wijnands]

And whatever it was has stopped. The survivors have perked up and yesterday I think I saw a mating dance again.

[CoryfanAad]

Great !!