Please Help!

[rachael99827]

i am currently house sitting for some friends for 5 weeks. and they have a whole glass house filled with fish. i know nothing about fish. and they are sick. really sick. the "outbreak" started the day before the owners left. we found about 10 dead fish in a tank and changed the water. all seemed well, the owners left...but then......things got worse. six dead here, seven dead there. then it started spreading to other tanks. it seems like when i do a water change things get better for a day or two but then more start dying.

yesterday things took a really bad turn. i spent a few hours pulling out dead fish....between 150-200. no that is not an exaggeration. today i haven't counted the dead bodies yet, but i have removed them. it looks like even MORE than yesterday. i started taking notes on behavior....here it goes: they have white cloudy film hanging from them. yesterday it was just some of them, today it is all of them. they have red scratches on their skin as well. they swim upside down, and some of the bottom feeders seem to be trying to commit suicide by "beaching"themselves on things in the tank. they all look like they are dying and i have pretty much lost hope on this tank. since about 400-500 have died in TWO days! and the rest look like they are on the verge of death. i am more worried about the other tanks. this started in one tank, spread to the one next to it (where the mass deaths are happening currently) and i am noticing other tanks are having one or two dead fish a day, and are not eating.

i am taking care of thousands of fish, i do not know what kind of fish, what size the tanks are other than that they are "big". i've been looking online about what it could be, and so far i think it is white spot (ichthyophthirius) BUT i also don't think it is, because they don't have white pimples, they have white cloudyness stringing from them. maybe it's a bacterial or fungal disease, but would that kill them in such a mass? i just don't know what to do, and would like the owners to come home to at least some fish.

 

[Ninjouzata]

Can you get a picture of some of the affected fish? This should help hopefully figure out what type of disease they have.
 
Perhaps start measuring the tanks as well? You can plug in the dimensions at the top of the page to give you the volume.
 
Can you call your friends? I'd hope with these many fish and tanks they'd have a list of fish that are in them and such.
 
Do you know if they have test kits?
 
When you're doing water changes and taking out dead fish, are you using the same instruments or different ones? If you're using the same ones that is likely helping to spread whatever this is.
 
For posting pictures you can upload them to a photo sharing website such as photo bucket and then link them here.

 

[majerah1]

I can say the red is septicemia caused from poor water. Sounds like columnaris as well, but without pictures and tank specifics it is too hard make an accurate guess. 

 

[eaglesaquarium]

Approximately how big is this tank with 150-200 dead fish at one time? 

 

[TwoTankAmin]

Are you using dechlorinator? Is this well water? The fish want out of the water really badly, something in it is killing them. I am not so certain is is a disease. If it isn't chlorine, it could be ammonia.
 
Are the filters working?
 
Do you know if the owners had recent plumbing work?
 
Is there and aerosol system of any sort in the glass house?
 
Look for some way something toxic could easily have gotten into all the tanks. Especially something airborne.
 
If it is a disease, it sounds virulent and rapidly fatal. It spreads easily, possibly airborne. If its something like this, you probably have one shot to pick a treatment and cross your fingers. Do you know if the owners recently got new fish or plants?

 

[RCA]

In respect to the bottom feeders breaching themselves, I would say there is definitely something wrong with the water, as they are trying to get away from it. I recently had a problem with a cycled tank and mature filter, which after a clean of the filter (in the usual correct way with aquarium water etc.) my fishes behaviour changed. My kuhlis were hanging over the heater, and the shrimps at the top. When I checked the water with the test kit the Nitrites were mega high. It took three days to get it stable again, and luckily no losses, but I had to move fast, and do large water changes daily, adding Seachem Prime with each change. Do you know if the owners did any maintenance prior to going away, and if so what?

If you can answer the questions already posted then we can help pinpoint the potential issue, and help get things back on track.

Definitely avoid using nets from one tank to another. Ideally, each tank should have their own nets or they should be sterilised with Methylene Blue, or poor boiling water over them and allow them to dry if possible in the interim.