Sudden deaths......

[fishycanuck]

Not sure what's going on.
Last week, in the space of 24 hours, I lost a discus, a crayfish, and a serpae tetra from the same tank.
The discus had been looking thin the day before, no signs of injury or illness otherwise. The crayfish - well, I thought I'd removed all the crays from my tank months ago. The tetra didn't bother me much, they're pretty old. I was pretty unhappy about it all,though, the discus are expensive.
I tested the water, no unusual parameters, and did three 50% pwc in the next three days.
Forward about a week -
I have a discus lying on the bottom of the tank. Fins look a bit worn. One of the other discus has a white spot, so I've elected to treat for ich. I don't have any Melafix so am using aquarium salt.
The parameters, today and most every day -
65G tank, established about a year ago.
All fish are old or purchased from a reliable local breeder.
Temp 84
pH 6.4
nitrItes 0
nitrAtes <20 (the test strip does not have a colour pad for 10 but I bet that's where it is)
no Chlorine.

The fish are fed beefheart and flake, the beefheart from the same breeder I get the discus from.
just did another 50% pwc and rinsed out the Eheim filter media (not sure when I did that last)

So, what's happening? How to proceed from here? 

[dan2x38]

Has there been any major temp swings in your home? There's been some wild rain down pours and sewage spills. At these times the City adds more chloramine to the water - it is actually automated in the water treatment facilities. You can go online (forget the link) and see when these increases may have happened. In any case there might have been a spike in chloramine and if you were only treating the normal amount it might not have been removed completely. In these cases I double dose the entire volume of the tank using Prime when I do a water change. This is safe Prime can be dosed x5. Chloramine doesn't evaporate so it can be left at higher levels in a tank if not treated enough.

To me this is way more common than many people believe or even know - IMHO. A way to over come this potential issue is a simple WC double dosing for the entire tank in your case 65 gal. be 3 capfuls of Prime basically. That will break down any excess chloramine and detox any harmful nitrogen compounds if present plus remove any heavy metals.

I swear by Prime and use it only doubling up especially during major run offs. I swear by the stuff!

[fishycanuck]

Hi Dan - temperature swings? Not really. We have air conditioning, but haven't put it on in the past few days. I was wondering about the Chloramine, and will dose as you suggest. Thanks.
Today the discus in question is definitely ich-y.

Correction: the pH is stable at 6.8

[Chinaman]

Hello there,

I keep discus but don't claim to be an expert in discus. It
seems, by your earlier account  that your discus may be
carrying some kind of latent diseases. Do they have the normal
appetite, just wonder?  With your tank temp at 80's ichs should not
be a cause.  Just my take.

Good luck,

Sam,

[dan2x38]

Many believe Ich lives dormant in our aquariums and in our fish but this is totally untrue. They are a parasite that lives off a host and once they are killed off they only reappear from another host - a fish invested with them. So if you didn't introduce anything new it isn't Ich. But as Chinaman says it sounds like a latent disease. I read that 80% of our fish carry tuberculosis and when the immune system is compromised it takes over. Once our fish become weakened by anything they are susceptible to many things. Good Luck sure hope things balance out again for you!

[Fishnut]

It's really hard to say wht might be going on.  Double check your water conditioner for sure.  There are times when the city adds more chloramine to the water.  I lost fish to that the first time I experienced it in this city.  I now double up on my water conditioner...only I use Aqua Plus.  I would suspect a spike in the chloramine levels has weakened your fish, which may have led to the disease.  The loss of the crayfish is a great indication that it was something external first.  I don't believe there are many diseases that will take out a crayfish that it caught from a fish.

From my experience, Discus need a varied diet.  Beefheart and flakes are ok, but add some blood worms, some brine shrimp, some daphnia and use a mixture of different brands of prepared foods.  IMO, if it's cheep food, you'll get cheap results with your fish.

[fishycanuck]

Thanks for the comments. Now I'm not sure it's ich any more.... but both fish are hanging in. I have not introduced anything to the tank in months.
The beefheart is a mix containing lots of stuff - I had a look at the recipe and decided it was too much trouble for me! it's certainly not cheap. I do give the fish a cube of bloodworms once a week.

[dan2x38]

If want you can have a flat of frozen daphina I have left. It is a big piece in other words a lot well worth the drive... :-)

[fishycanuck]

I sent photos of the discus to the breeder, and she diagnosed an external parasite. Likely from an old pleco I had transferred from another tank weeks before and forgotten about!
Sadly, the two discus are dead - but I've got the gravel and decorations soaking in peroxide, and have treated both my tanks with Aquari-sol.
Thanks for the help!