Sudden Angelfish Death

Last night all was well in my tank. However this morning I awake to find my 3 year old golden angelfish dead. There was no visible signs of injury or disease. What's the likely hood that he will transmit something to my other fish?

It wasn't old age.

So it wasn't killed by another fish or parasites.

So, it was eather bacterial or poor water quality. Eather could and likely will, harm or kill other fish.......Frank

Well, we've had no more losses yet in that tank. I did a 25% change the night after he died. Let's talk about water quality, everyone always points to that but really what is a test kit going to tell you. I just bought a new test kit and everything according to it is 'Normal'. I've tested Nitrites / Nitrates, Ammonia and PH. This tank has some plants in it and they're doing fine. I would think that bad water quality wouldn't allow the plants to survive.. Or am I wrong?

There are certain aquatic conditions that are more amenable to plants than to fish.

That depends on whether the sudden demise was due to infectious disease or something sudden like a heart attack, which are not

Lets define water quality first, so we are on the same page. There are five points to look at - - - #1 - organic pollution (DOCs = dissolved organic compounds) #2 - inorganic compounds = ammonia, nitrite, nitrate. #3 - dH, pH, temperature. #4 - chemically clean (ie; chlorine, heavy metals, medications, organophosphates. #5 - stability not fluctuation.

Which test is in guestion?

Yes, you are wrong. ie; #1 above - DOCs are an endless supply of plant nutrients, but can kill fish. #2 above - again, plants love inorganic compounds, but in high levels, kills fish. #3 above - etc. etc.... Frank

Ok.. for example I get these readings using this 'Fresh Lab' by Red Sea states I have the following in the tank that just lost the fish:

Temperature is 74 deg F PH is 7.4 NH3/NH4: 0 PPM NO2: 0.05 PPM

Any other tests I'm missing here? I know with plants I should have an Iron test however nothing at the LFS carries this, and it seems silly to mail order a test kit for 12.00 and pay 11$ for shipping.

Through the winter, I keep my tanks between 76º and 78º. Smaller tanks can fluctuate with someone standing at an open exterior door to long.

In an established tank, it's usually fluctuation that stresses the fish. A swing in pH, dH, kH, temp., and ammonia/nitrite levels can do it, but *most* of the time it's eather a build-up of DOCs (organic pollution) or to great of a change in osmotic pressure. With an aged tank, that can happen with a large water change, anything over 20%. Even high levels of nitrAte will stress fish. Example - typical symptoms that are over looked are; repetitive excape movements, repeatedly bumping glass, back and forth movements, and up and down cornors - most of the time when a fish does any of the above, it is in stress. Stressed fish include the secretion of stress hormones called Pheromons. These hormones affect the behavior of other fish if secreted in large amounts, or over a long period of time, having undesirable health effects. Meanwhile, chronic stress sets in on the fish that suffered a little stress to begain with. The fish weakens, immune system fails, and the fish dies - all while everything looks normal. With a newly set-up tank, the fulctuation in parameters between your water and what's in the pet shops tanks could (and does) kill fish all the time.

Most people don't keep up with the weekly tank maintenance and eather have the wrong type of filter for their tank, or don't know how to set it up right. These tanks suffer from organic pollution - high levels of DOCs, and TDS (total dissolved solids). DOCs are not detected by a chemical hardness test, however they will measure on a conductivity meter.Both test will determine DOC by comparing the differences between the two. A kH test kit is good to have around. kH = carbonate hardness - buffering capacity and alkalinity. Waters buffering capacity is due to carbonates and bicarbonates which gives the water ability to keep pH stable. kH below 4.5dH will cause unstable pH. pH drops, ammonia becomes non-toxic ammonium which builds up. With a water change, the buffer is suddenly restored and ammonium reconverts to its toxic form, ammonia. Water chemistry has 4 properties you should have a test kit for - pH, buffering capacity, general hardness, and salinity. Skip the hydrometer (salinity) for now and get a conductivity meter for checking DOC levels.......... Frank

the only thing I have seen that seems off is the temperature. Angels seem to do best kept around 78-80. The stress of the cooler temperatures MIGHT have just worn him down..

John, sometimes you have to listen to the wisdom of a more skilled and experienced aquarist.

It's funny you said that.. I just made that tweak to the tank today. It's been a bad day here, the whole city was w/o power for most of the time I was away at work for a total of 8 hours. It's all powered up now and looking for the injured. It's like a nightmare when the power goes out in the winter... the house got to 60ish and the tanks where in the high 60's.