Struggling with Botia kubotai

[Zombarista]

Hi, I'm new here. I need advice with my loaches generally, but in this case with my polka-dot loaches specifically.

My tank is 125L, has been set up two years (it was previously 250L but due to the old one leaking we had to have an emergency downsize). We used to own five Botia almorhae but a few months back they began dying with no obvious symptoms, one followed another over the course of four weeks. There had been no additions to the tank during this time. We left things to calm down for three months before last week trying to add 5 polka-dot loaches. Two of these died within 24 hours, one died another day later, and the remaining two look stressed and uncomfortable. Their gills are moving rapidly and they are moving jerkily although otherwise look healthy. They are completely uninterested in food. Our tank is very well aerated as we have two powerheads and an additional air pump. We have kuhlis in our tank since the beginning and they are thriving.

* Filtered by standard Juwel internal filter plus additional Fluval 205
* Temp 25C
* NH3/NO2 are reading zero ppm, NO3 is 10ppm, pH 6.5. Water is soft.
* Water changes are 25% weekly
* Tankmates - Harlequin rasbora, Blackskirt tetras, cardinal tetras, cherry barbs, kuhli loaches, corydoras rabauti, trilineatus, and caudimaculatus.

Any advice would be greatly appreciated.

Thanks,

Dave

[Diana]

I am afraid that the emergency downsize may be part of the problem. Your fish list is already too many for the tank, and adding more just stresses the system even more.

Double check the results of your water test either with a different test kit or by taking a sample to a store. It seems impossible that that many fish and those small water changes are keeping the nitrate so low.

To acclimate fish to a new tank:
1) set up a quarantine tank.
2) Test the water the fish are in, test the bag of water you bring the fish home in.
3) Set up the Q-tank to match the GH, KH, pH and especially the TDS (if you have a meter). The stress symptoms you are seeing suggests the fish are having osmoregulatory issues. This means the water they were in at the store has a different level of minerals than your water at home.
4) While the fish are in quarantine monitor them for any disease they may have brought with them, and treat for internal parasites. Many bottom feeding fish pick up more than an average amount of these parasites, then the stress of capture, shipping and so on lowers the immunity of these fish and the parasites and diseases take over.
5) While the fish are in quarantine do small, frequent water changes to gradually alter their water to match the main tank.

[Zombarista]

Thanks for your reply. I have two test kits and they confirm the numbers are correct - this tank is heavily planted which would explain the low nitrate readings.

Thanks for the advice regarding the quarantine conditions that sounds like a good idea, I'd been acclimating using the drip method over several hours before but it does seem as if slower more gradual changes would be better. I do make an effort to buy from LFS with the same water supply as me.

When you say treat for internal parasites, is this something you'd do as a matter of course, whether or not they showed any symptoms of infection?

Thanks again, I appreciate it!

[plaalye]

I had the same thoughts as Diana. It sounds way overcrowded with some incompatible species and too many bottom dwellers. This could lead to aggressive behavior. Is there anything in the tank that could be leaching toxins? Maybe get a TDS meter and have a look? How long is the tank? I wouldn't keep botias, especially almorhae, in less than 36", 48" better!

Everyone has their own quarantine routine but I have been treating all new fish with flubendazole since I discovered it. It's easy, doesn't seem to harm anything else in the tank except for snails(good riddance!), and takes care of internal parasites as well as ich, velvet etc.

Good luck figuring out your problem!