Fish Dying

[iluvguppies]

Hi,

I have:

64l freshwater tropical tank
temp 25C
Ammonia 0
Nitrite 0
Nitrate 40-60...hard to tell colour but I think it's 40...I've since done a 70% water change so it should be lower but haven't re checked yet.
pH 7.4

My tank was set up at the end of June this year. It was a fish-in cycle and lasted about 7 weeks. I lost about 3 fish in the first week and then I didn't lose anymore. My tank has been cycled for almost 2 months.
Fish, originally:

6 neon tetras
3 guppies
5 1" albino cories

The fish all seem ok..no obvious signs of illness.....eating well, swimming normally, normal behaviour, no injuries or marks etc on them.

The problem is that since about a month ago I've lost 3 cories and 1 guppy. I first lost 2 cories in about a week ..they died a few days apart (about a month ago), they were lethargic for a few days beforehand but other than that no apparent symptoms. I then lost a guppy last week and today another cory...these fish showed no apparent symptoms and overnight just turned up dead.

All bodies appeared fairly normal, although this last one had slightly red gills (he may have been dead about 24-30hrs before I found him). I previously dosed the tank with myxazin for 5 days after the 2nd death.

Any ideas??

Advice appreciated

Nikki

 

[Curiosity101]

I would presume that it's simply the repercussion of them being put through fish-in cycling. Ammonia and nitrite are toxic, although people aim to keep them below 0.25 during a fish-in cycle, these levels are easily high enough to cause lasting damage.

Fish put through fish-in cycles have considerably shorter lives, and are often more prone to diseases.

Presuming your water stats hold and there are no signs of contagious illness (Eg. Whitespot), I would just keep an eye on things. And begin to very slowly restock.

 

[iluvguppies]

Thanks for replying so fast

I didn't know about fishless cycle until after I got my fish (lfs didnt mention it and I was ignorant of it til I found this website).

Do you think that I'm likely to lose the rest, then?

I'm planning to upgrade very soon...should I disinfect all the gravel and fake plants to make sure no germs are left? Would I need to somehow clean the filters and foams? Don't want to have to cycle again though unless imperative.

Thnx,

Nikki

 

[Curiosity101]

Each fish reacts differently (well different levels of badly anyways lol), to a fish in cycle. I can guarantee all the fish will have a shortened lifespan, but I can't say how short. Just treat them as you would any other fish and give them the best life you can

And no, realllllly no need to disinfect anything. Only clean the filter pads in old tank water when the filter flow slows and you should never need to cycle a tank again.
Once you've done it once and you're simple upgrading then you just put the cycled pads in any upgraded filter alongside the new filters pads and away you go.

If you ever set up a completely new tank (ie. not moving any fish across, simply buying new). Then you just take some of your mature media, implant in new filter, and do a super fast fishless cycle.