My Guppies are dead and Gourami is sick...

[senemedar]

A few days back two of my Guppies died suddenly, and another few was swimming just under the surface. I tested the water straight away and numbers were high.
After three water changes and two days, numbers went down to 0 except for the Nitrite which is still between 0 and 0.1. In the meantime another six Guppies died. Yesterday everything was OK, remaining four Guppies swimming happily, and water tested OK (except for the Nitrites, still between 0 and 0.1). I changed the water again and went to sleep thinking everything's gonna be fine now.

This morning another Guppie was dead, other one swimming just under surface and third one has half of his tail eaten away.

Other fishes seems to be unaffected, except for Dwarf Gourami, who's getting all black under the belly and is not eating for two days.

What is wrong? I read, that Dwarf Gourami's can carry some diseases-- is that what killed my Guppies?
I know about Nitrite/Nitrate poisoning (swimming under surface) but the my water's OK now and they still dying... I don't know what to do now... ;(

 

[librarygirl]

With ammonia and nitrites in the tank your tank isn't cycled. You need to keep ammonia and nitrite under .25 at all times (and nitrate under 20) with water changes. Use a good dechlorinator like Prime (it'll help detoxify the ammonia and nitrite between water changes). What test kit are you using? The API Master liquid kit is best. There's two links in my signature for you:"what is cycling' and 'new tank with fish." Keep up with testing daily and water changes as needed to keep those levels down; no more new fish until the tank cycles which could take a few weeks at least. In a properly cycled tank ammonia and nitrite will stay at 0 on their own and nitrates are kept below 20 through water changes, usually 1-2x per week. For now, until the tank establishes itself and cycles properly, testing and water changes. You may need to test and change water more than once per day and even do large water changes or back-to-back changes to keep the levels down, particularly nitrites which tend to want to spike. Good luck.

 

[senemedar]

Yes, I think the tank went into some kind of cycle when I messed with the filter; stupid me. I have the tank for about 10 months now and the filter was playing on me, so I decided to change it for a new one. Well, we all learn on our mistakes. For now my numbers are zeroed for second day in a row so I'm in good thoughts.

Unfortunately 8 out of my 12 Guppies didn't make it, and Dwarf Gourami is on a "finishing line" and I'm thinking about ending his suffering. Although I bought two Dwarf Gouramis at a time and a few months back one of them died with exactly the symptoms I see now, so I'm thinking that it may be a coincidence just now. I dunno......

 

[librarygirl]

Sorry about your fish. Did you move the old filter media into the new filter or just scrap everything and use new media? Getting a new filter itself would have been OK if you moved the old filter media into it. If not, then yes definitely a mini-cycle (or maybe not so mini). Just keep up with the water tests and changes as needed to keep those toxins down until the tank recycles. Gouramis are sensitive and they have their own disease, so it might have been sick already.

 

[senemedar]

Sorry about your fish. Did you move the old filter media into the new filter or just scrap everything and use new media? Getting a new filter itself would have been OK if you moved the old filter media into it. If not, then yes definitely a mini-cycle (or maybe not so mini). Just keep up with the water tests and changes as needed to keep those toxins down until the tank recycles. Gouramis are sensitive and they have their own disease, so it might have been sick already.

Yes, I moved the old media and that's where I went wrong; I packed it so tight that I almost stopped the water flow

The Gourami had died yesterday, even before I made my decision whether to euthanise it or not... At this moment I only have 5 fishes left from the one I started the tank with, almost year ago.