unexplained death

jimmyB · Post by **jimmyB** » 26 Jul 2004, 20:59

I have had a 15 gallon tank set up for 4-5 weeks. It has had 3 platies, and 2 corys for about a month now. I just recently purchased 2 additional corys, I believe they are Trilineatus, although the LFS calls them Juliis. The tank is bare-bottom, with one large live plant (potted), and a hang-on back filter, as well as an airstone, and a few hiding rocks with smooth edges. I keep the bottom vacuumed, and change about 30-35% of the water on a weekly basis - 2 changes of 15% at a time. My pH is 7.3. Everything has been going well, my friend tested the water for ammonia/nitrates and commented that my water changing and levels are very good, granted the # of fish in this tank is relatively low. For the first few days all 4 cories were swimming together and seemed to be doing great. I had been feeding them brine shrimp the day before, and a mix of spirulina flake and a krill flake prior to that. I know underfeeding was not a problem. So, 3 days after purchasing these 2 new cories, I notice one sitting in the same position for several hours. After nudging him with the net, I see that he has died. Any ideas? His eyes looked clear, in fact I thought he was still alive when I saw him sitting there during the day. I noticed that this poor little fellow had a red color visible around the front part of his body, under the skin. Almost like internal bleeding. No fungus or nipped fins or shredded whiskers, not a sign of problem on the outside. It is the visible red color that makes me wonder.

mkeanem · Post by **mkeanem** » 11 Aug 2004, 10:49

i had the same problem 2 weeks ago with cory's and i think in my tank it was rocks leeching stuff in to the water (in my case i think it was iron from my rocks)
have any of your rocks got viens in them that could be metal
also it could just be new tank syndrome and if it is just wait for tank to settle give it another month or so before adding any more fish and make sure you feed the cats with food specially for cats

Stevetd · Post by **Stevetd** » 11 Aug 2004, 11:54

Hi
Sorry to hear about your fish.
Are you saying that your tank had completely cycled?
I know with Pims that a reddening of the underside can be a reaction to
elevated ammonia levels?
When youy say your friend tested the water, how long later did the fish die?

Steve

Dcptherock · Post by **Dcptherock** » 16 Aug 2004, 21:43

It is a reaction to the ammonia levels

Post by **Coryman** » 16 Aug 2004, 23:02

Dcptherock

It is a reaction to the ammonia level

What makes you so positive?

jimmyB

C. trilineatus are one of a number of species that can actually poison themselves when being transported in a bag. What happens is when the fish are first caught they are put under stress and release a toxin into the water, the toxin will diminish the oxygen levels in the bag and in effect the fish poison themselves. This reaction from the freshly caught fish may well be a natural defense mechanism, in the event of being caught by a predator the toxins are exuded to cause the predator to let go.

The first signs of toxins being released is some foaming on the surface of the water in the bag. If this happens it is wise to ask the person serving you to re-bag the fish, this should prevent any further problems. The red blotches are usually a sign of the this kind of poisoning, if blotches are spotted early enough it is possible to save the fish by applying a full dose of Melafix, but when using this medication always add an extra air stone with a good flow to maximise the oxygen levels in the water.

Ian

certan · Post by **certan** » 16 Aug 2004, 23:09

Coryman wrote:...C. trilineatus are one of a number of species that can actually poison themselves when being transported in a bag...

Hi Ian,

What are the other species that poison themselves in such a case?

Post by **Coryman** » 17 Aug 2004, 01:08

The most common species that I have found are C. trilineatus C. metae and even C. sterbai. Mostly it seams to be the short nosed species that are more prone to react to stress in this way.

A lot depends on how the LFS keeps their fish, if they are constantly being disturbed and stressed trough nets in the tank and such like they will probably have purged themselves of toxins, but where Corys are being kept in ideal conditions and are not under much stress then these are the ones to keep an eye on once they are in a bag and the first sign of foaming at the surface get the water changed. Its probably not the right thing to say, but if you have a novice sales person catching your corys and chasing them around the tank a bit before they manage to catch them they are probably doing you a favor.

Ian