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-   -   Help!!! Establishing cause of death... (http://www.tropicalfishkeeping.com/characins/help-establishing-cause-death-23829/)

Bottomfeeder 05-10-2009 03:00 PM

Help!!! Establishing cause of death...
 
I just found one of my favorite fish floating :cry:
one of my Red Dwarf Pencilfish...
the other one is alive...slightly washed out and not eating flakes right in fron of it...but this happens occasionally...what happened? the fish was floating belly up and its colors were darkened...i havent seen anything suggesting they were sick.
i did an emergency water change before testing my water but i assume the pH is around 7.5...it usually is...also im slightly worried about the other one...not just because its an $8 fish but also because i really like them and my dad had to drive me 45 mins to get them :(

aquakid 05-10-2009 03:14 PM

In order to determine cause of death you would have to post your water parameters pictures of the dead fish. How long ago it died, the other tank inhabitants, and what else is in the tank.

Bottomfeeder 05-10-2009 03:18 PM

its a 5.5g tank with 2 (now 1) Red Dwarf Pencils, a Cobra Guppy, 2 Ottocinclus, an Amano, with a Tetra Whisper PF10. temp=78 dF
params i dont have...pics i dont have either...

Byron 05-10-2009 05:14 PM

How long has this tank been running? And when did you add the pencilfish?

Bottomfeeder 05-10-2009 05:19 PM

tank has been running 2-3months. Pencilfish have been residents for about a month.

Bottomfeeder 05-10-2009 05:54 PM

!!!!
the other one is just hiding in the plants...and the red is getting pale :(

Byron 05-10-2009 06:45 PM

2 Attachment(s)
It's sometimes difficult to diagnose why a fish dies, but I will share a couple of observations. I have maintained several of the pencilfish species over the years. Common names are not always reliable, so I'm not sure if you have the common dwarf pencilfish Nannostomus marginatus, or the coral red dwarf pencilfish Nannostomus mortenthaleri, or even some other fish. I've tracked down a couple of photos and attached them; the left photo is N. marginatus and the right photo is N. mortenthaleri.

Most of the pencilfishes are wild caught and they are not the easiest to adapt to water that is significantly different from their native habitat. The dwarf pencilfish, species Nannostomus marginatus, comes from several sites in the Amazon basin, notably the Rio Negro and its tributaries. The water in the Rio Negro is very soft (there is basically no mineral content to speak of) and has a pH of 3.4 to 5.5 depending upon localities. The N. mortenthaleri comes from forest tributaries of the Rio Nanay in northern Peru. I would expect the water to be acidic, although probably not as much so as the Rio Negro. Each degree in the pH scale (from 5 to 6 for example) represents a ten-fold change in acidity, so a pH of 6 is ten times more acidic that pH 7.0, and pH 5 is 100 times more acidic that pH 7.0, etc. This is quite a variance from your tank's pH of 7.5 and I suspect your water is on the hard rather than soft side in its mineral content. Pencilfish are sensitive to water chemistry and do not always adapt easily to water that is vastly different. I've mentioned in other threads the reason for this.

Another possible problem could be the aggressiveness of males particularly with N. mortenthaleri. I have not managed to find any of this beautiful species myself, but in an account of this fish in Practical Fishkeeping, Dr Karel Zahradka reports that in a restricted space (too small tanks) the males will kill each other. I have read elsewhere that this occurs with many of the pencilfish. Did you notice any aggression between the two fish you had? The lack of colour and non-eating are sometimes indications that the fish is being "bullied."

A related point is that pencilfish are characins, and like tetras (also characins) they are shoaling fish that prefer to be kept in groups. There are several tetras where the males will become more aggressive if they are kept 2 or 3, whereas in groups of 6 or more there is less direct aggression. But this of course requires a larger tank.

The above are a couple of reasons, and of course it is always possible that the fish carried some internal parasite or abnormality. But for the future, I would suggest providing pencilfish with water closer to their natural environment, slightly acidic (pH 6.5-7.0) and in small groups.

Bottomfeeder 05-10-2009 07:17 PM

the fish seemed completely healthy up until today, and in the store they were in a tank that was connected to over 50 other tanks running on a central system with fish from all over the world. i dont think they were in water with any adjusted pH...and they are closest to the left picture but not exact.
and no they werent bullying at all...

Byron 05-10-2009 07:46 PM

Quote:

Originally Posted by Bottomfeeder (Post 194290)
the fish seemed completely healthy up until today, and in the store they were in a tank that was connected to over 50 other tanks running on a central system with fish from all over the world. i dont think they were in water with any adjusted pH...and they are closest to the left picture but not exact.
and no they werent bullying at all...

It is interesting how fish can sometimes continue "normal' (as we observe them) but eventually enough is enough and they weaken and that can be sudden (in my experience). Any idea what the pH and hardness of the lfs water is? Many lfs treat their water to maintain a constant pH of 7 which is fairly broad for most of the fish they sell, and in the short term even discus can handle this. But, as I noted before, I am not saying any of my former suggestions are the definitive reason--they are possibilities.

Bottomfeeder 05-10-2009 07:56 PM

No, sorry i didnt ask :(
i just dont wanna loose him, hes one of my favorites... *sigh*


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