Suicidal plecos????

With that water quality, there sholdnt be any live creature inside...
Where is 9+ pH normal? In Tanganika may be...
Anyway, the problem is the water quality; so first thing to do is make a complete water change... but, do you have enough good quality water stock?
Well, as you see, you also need a good water quality tester.
Hope there are still some survivals in your tank...
 
admittedly, I found the results slightly suspect myself, she was using those "quickdip" strips, however i remember the last time i had a test kit(can't remember what brand) i remember the ph was outrageously high, even after an RO filter and water softener. weird thing was, when i had tried lowering it with PHdown, it dropped my ph really low and killed off almost my entire tank, except my oscars i had at the time
Test strips never work properly...coincidently the ones I used to use before I knew any better always said my pH was higher than it actually was.
 
Here's a thought, go with the test strips being right, stop feeding, do a 50% water change now, again in a few hours, again tomorrow morning, then go test again. It's not going to hurt anything but the symptoms you were describing SOUND like ammonia so the test kits being wrong or right is really moot. It sounds like someone is helping you feed fish or something, if I had to guess.

Barbie
 
I know in my tank that if something is "off", my pleco is the first to let me know about it by coming to the surface hard like he's trying to get out. When he starts doing that, I normally find a platy or guppy has died in the plants somewhere. I've had him for 5 years, and it's the only time he does that.
 
so, I finally had my water tested last night, the tests came back.... ammonia 10 ppm, nitrite 10ppm, nitrate 20 ppm, and ph 9.0+(she said it's normal ph for this area????) any natural ways I can lower ph??? ammonia and nitrite make sense, since I just combined my 2 tanks after the fireworks settled down a couple of days ago. I also had talked to my dad, he used to have an angel tank about 20 years ago. my mom had went and bought a few blue paradise gouramis "to add color to the tank". they got along fine for about a year, then one day my dad came home to find all 10 angels dead, apparently from the gouramis....
Wow your ammonia and nitrites are high, keep doing water changes until they go back to 0 ppm. I don't ever let my nitrates ever go above 20 ppm so when i see them at 20 it's time to change some water.
Heavily polluted water can make your ph rise.
 
OMG. I don't think anything could survive those parameters, and the quick dip strips are useless, IMO. Get an API liquid test kit ASAP and test those parameters. Until then, do water changes, water changes, water changes. If your ammonia and nitrite are anywhere near what the LFS told you, it's no wonder your pleco committed suicide, he was just trying to put himself out of his misery. :(
 
Just as an update - I ended up doing a complete teardown, turns out we have to move, so now everyone that survived is in a temporary holding tank at my dad's until after we move. Apparently my substrate must have been part of the prob - my tank is currently bare except for some larger rocks, and I haven't had any water quality probs yet. When I was tearing down, I emptied the substrate out completely (the pet store multicolored gravel, man did it STINK!!!!) and found a large accumulation of detritus, as well as several long dead occupants who went missing months ago. After we move, I'm planning on getting fine grain sand to prevent this kind of problem in the future.
 
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