Regardless of pet store QT, one should always QT their fish, especially ones like gouramis and labyrinth fish. Those should be QT'd a minimum of a month since gourami's especially can carry some rather nasty, and incurable illnesses.

Adding gourami's together, even in large tanks, can also be iffy. They may have gotten along at one point, but sometimes, usually, lose tolerance to the others eventually.

So yes, if you get another, QT it first in a smaller, easier to treat tank over putting it in the larger tank which may spread a nasty to the whole thing requiring treatment of the tank itself in some cases.

 

I have found that Dwarf Gouramis are usually the more aggressive too.

 

Gouramis in general don't need to be quarantined any more than any other fish. The only gourami specific disease that I am aware of is dwarf gourami disease, which only affects DGs - not other gourami species. And since one shouldn't be keeping multiple DGs together, the concern about quarantining and DGD is a moot point.

 

So based upon the info provided, do I QT the one DG that I have? He has been in my 55 gallon tank for several months and was apparently well. The in came the LFS new DG, who quickly sickened/was euthanized. Original DG immediately began hiding and acting weird. But better than before.

Current symptoms: He still looks bloated. Normal waste that I have observed. Still hanging low in the tank, but not at a 45 degree angle like before. He is eating, but slowly. He is swimming to the top, but slowly. I don't see him curving into a c shape anymore. He does seem to drift in the HOB Penguin Biowheel filter current.

Since whole tank already exposed and treated with Quick Cure x 5 days, do I QT the DG and treat with antibiotics instead? I have erythromycin.

My QT is in the midst of a quick cycle (this morning parameter Ammonia, Nitrites both 0.25, Nitrates 5).

 

It's always best to quarantine new fish. But your DG is not new. If a fish is acting weird and I can't figure out why, I will separate the fish for further observation. Of course that's only helpful if the tank the fish is being moved to is cycled, otherwise the stress associated with being in an uncycled tank can make observing it's problematic behavior an issue.

 

If you're adding any fish to a community tank it should go in QT for a while for observation. Back in the day when I was a wholesaler, gouramis used to come in with this odd slime coat issue that was a combo of bacteria, parasites and secondary fungal infection. We used Formalin and a braod spectrum antibiotic. We would later dose with salt and Meth Blue. If you purchase gouramis ask where the store got them from. Some farms raise and or sell Florida fish only, other import. The imports are a problem.

 

Thanks for the advice