Fish Death....

[DavidG]

We have recently completed a very long and slow fishless cycle and have finally added two fish to our tank. We added two harlequin rasboras 8 days ago with the view of getting a couple more in a week or twos time rather than rushing in and stocking fully right from the off.

Everything seemed to be going well.... fed them once daily a very small amount, one small flake crushed up. Two days in we realised the heater had packed up so we replaced immediately and everything was fine once again.

Yesterday we did a weekly 50% water change, refilling with decholorinator at 1.5-2 times the recommended rate (Tetra Aquasafe) and replaced the carbon clean and clear sachet in the filter; one third of the total filter.

Today I decided not feed them as other posts had suggested only feeding 6 out of 7 days and unfortunately I received a call at work from my other half to say that one of them had died after she got home with the kids

. Both fishes were swimming around when she got home with the kids but one died soon afterwards.

The dead fish was removed immediately and I have tested all the levels as soon as I got in this evening and everything appears fine. Readings were

pH = 7.5-8.0 (the same level as my tap water)
Ammonia = 0
Nitrite = 0
Nitrate = less than 5ppm

Tank temp = 24 deg C

I am scratching my head as to what has gone wrong. We did notice a small difference in the colouration of the two fish. One had a darker more pronounced wedge shape under its dorsal fin whereas the one that died had a paler less defined marking. We took this to mean that the fish with the less defined marking was female.

The other fish is still swimming around at all levels of the tank and seems happy. Does anyone have any ideas or thoughts on what might have gone wrong? Or could the fish have been ill or someting and it is just one of those unfortunate things that happens sometimes?

Any help would be greatly appreciated....

EDIT - We have a Fluval Edge tank with an upgraded 50W heaterset to 24 deg C. The fluval edge heater packed up and I preferred the idea of being able to accurately set the temp. Lights on for a couple of hours in the evening.

 

[Mo1959]

Strange. They are supposed to be hardy fish but I had a terrible batch as well that just seemed very poorly from the start. Maybe you have just been unlucky as your stats are all fine.

 

[Harlequins]

Sorry to hear you lost a fish,harlequins are usually pretty hardy...

How long did you do your fishless cycle for?

In theory if your ammonia & nitrite was clearing within 12 hours,then you could have put more fish in to start with or your bacteria will start to die off.

TBH changing the carbon in the filter isn't really necessary,carbon is mainly used for removing meds or tannins out of the tank,and you would probably be better putting more media in its place.
Removing the carbon you probably removed some of the bacteria that grew on the carbon,but has your stats seem ok it hasn't troubled it too much...

If your water stats remain ok i would add some more harlequins,they're shoaling fish and will do better in a group.

 

[DavidG]

Thanks for the replies so far...

Strange. They are supposed to be hardy fish but I had a terrible batch as well that just seemed very poorly from the start. Maybe you have just been unlucky as your stats are all fine.

Am hoping the same thing Mo.

Sorry to hear you lost a fish,harlequins are usually pretty hardy...

How long did you do your fishless cycle for?

In theory if your ammonia & nitrite was clearing within 12 hours,then you could have put more fish in to start with or your bacteria will start to die off.

TBH changing the carbon in the filter isn't really necessary,carbon is mainly used for removing meds or tannins out of the tank,and you would probably be better putting more media in its place.
Removing the carbon you probably removed some of the bacteria that grew on the carbon,but has your stats seem ok it hasn't troubled it too much...

If your water stats remain ok i would add some more harlequins,they're shoaling fish and will do better in a group.

The cycle went on for three months which I think was due in part to not being able to get the tank up to a high enough temperature to help move things along but we perservered.

TBH honest I changed the carbon bag that sits in the middle of the Fluval Edge 3 stage filter because I thought it was probably in need of it as I had not changed it before and it had been up and running for over three months. Maybe I shouldnt have in hindsight but as the stats all seem ok I am not sure it is that that has killed the fish.

We are going to try and get a couple more tomorrow which hopefully should leave space for 4 cardinal tetras in a few weeks time...

 

[Harlequins]

How big is your tank?

Shoaling fish like harlequins and tetras do betters in higher numbers than 4 of each.

 

[DavidG]

Its a Fluval Edge which is 23 litres (6 gallons) so I'd thought that I would probably go for six small fish in total to avoid overstocking.

 

[DavidG]

We bought a couple more harlequins yesterday. All seem fine but unfortunately the remaining one from the first batch died last night so now we only have two left. Tested water again and all stats are zero.

Had hoped that by fishless cycling the tank first we would have avoided fish deaths and now I'm a bit stuck as to what to do for the best. Do we add more to bring the numbers up to six in total or do we wait a couple of weeks and if none die add four more then?

 

[Littlemonkey]

It could be that they were not that healthy to start with. Try changing where you buy them from. Don't lose heart.

 

[DavidG]

Thanks Littlemonkey... will try not to... just got to break the news to the kids now and I'm sure they will be upset. We did buy the second batch from a different shop so will see how they fair. Is it best to wait and see how these two get on before adding more? Or should we add more straight away to bring the numbers up so there is a small shoal?

 

[Skins]

It could be that they were not that healthy to start with. Try changing where you buy them from. Don't lose heart.

+1,
Yes, try not to lose heart. I lost one of my fish today, i had him only a month and he never seemed happy from the start.
Yesturday i was down all day, what made things worse was i could not get any clove oil for love or money.

Skins.

 

[DavidG]

Sorry to hear about your loss today Skins. What do you use clove oil for?

Is it best though to leave the remaining two for a couple of weeks before adding any more?

 

[Littlemonkey]

I would personally. Your stats seem fine, as you got these from another source fingers crossed that all will go well. We have all suffered (being sold unhealthy fish) at one time or another, you are not alone.

 

[DavidG]

Ok thanks Littlemonkey. Will leave the two by themselves for the time being and see what happens over the next fortnight before I do anything else. Fingers crossed.

 

[the_lock_man]

It could be that they were not that healthy to start with. Try changing where you buy them from. Don't lose heart.

+1,
Yes, try not to lose heart. I lost one of my fish today, i had him only a month and he never seemed happy from the start.
Yesturday i was down all day, what made things worse was i could not get any clove oil for love or money.

Skins.

Skins, I got my clove oil from Sainsburys pharmacy - I'd assume that it's a standard stock line at all Sainsburys pharmacy departments. It's a "Behind the Counter" product, rather than the normal shelves.

Sorry to hear about your loss today Skins. What do you use clove oil for?

Is it best though to leave the remaining two for a couple of weeks before adding any more?

It's used for putting very ill fish to sleep. Not a pleasant job, but better than watching them suffer.

 

[Skins]

[/quote]

Skins, I got my clove oil from Sainsburys pharmacy - I'd assume that it's a standard stock line at all Sainsburys pharmacy departments. It's a "Behind the Counter" product, rather than the normal shelves.

Thankyou the_lock_man