Unexplained fish deaths . Help

[nebulous]

I've had fish tanks for years and recently had a bunch of unexplained fish deaths.

I have a 40gallon high tank that I set up about five months ago.
Aqua clear 50 filter with 2 foam inserts and one bio media insert.
Fluval heater 200 watt
Sand substrate. Bought from petsmart
Live plants. Low light.
Water from tap. Treated with prime.

I stocked the tank initially with 4 glo fish a pleco I was doing water changes via bucket for a while and all was good

I bought an automatic water changer. Aquion. After using it 2 glo fish died.

I waited a good month and a half and stocked the tank with angels. The angels started dying soon after. I went through about 8 angels and a bn pleco.

I waited a month and then bought a khuli loach 5 panda cories 6 cardinal tetras. I had 2 glo fish from the first batch of fish and a bn pleco from the angels as well as a snail bought with the other new fish in the tank.

The loach died the day after putting him in the tank. The cories are dying one after another and my bn just died this morning.

No fish has any symptoms of disease

I changed out my heater and the foam media recently and bought new plants.

Water parameters are all fine. Ammonia 0. Nitrite 0. Nitrate 20. Ph is fine. Liquid test kit used

I started using the auto changer adding prime while adding water and now drain the tank, add prime and wait a few minutes before adding new water. I match temperature to tank water.

Could it be something to do with the auto syphon or maybe oxygen levels?

I am T a loss as to what to do. My ten gallon with a betta only in it has been treated the same and no issues at all with that tank. It's been set up 2 months so far and water has been hanged both by bucket and auto syphon.

 

[jlk]

How are you acclimating your new fish? Are you quaratining them? Where are you buying them from? Are you dosing Prime to the full size of your tank (not the amount changed) when you do water changes using the Aqueon? Do you keep the end of the hose submerged in the tank when filling? How do your tap parameters look, including ph? Whats your tanks ph? Do you know if chlorine or chloramine is used in your tap? Just thinking of things of the top of my head that may be a cause for concern because your tank numbers appear fine.

 

[Hholly]

Also, what are the symptoms? How do they act before they die?

 

[nebulous]

Ok. Acclimate via floating bag method. I dose prime for the whole tank. Ph is 7.4 using high ph test and low ph reads blue. 7.6. The fish show no symptoms prior to death although the bn got pale a day or so before death. No gasping at surface either.

 

[nebulous]

I buy fish from Los exclusively. I keep the hose end submerged mostly during water changes. Not sure about chlorine or chloramines but prime should take care of that right?

 

[jlk]

Hmm... i would suggest drip acclimating any future fish just as a simple precaution. Yes, Prime should handle any chlorine/cholramine but if you have very high levels, a standard dose may not be sufficient. You should be able to check your water reports online if you search your municipality/water authority. There should also be warnings if theres something that is unusually high such as lead or copper. Theres nothing else that stands out as a red flag unless your fish supplier just simply has a very poor stock of fish. Perhaps you can try purchasing a single fish or two from somewhere else, drip acclimating them and see what happens. Im honestly not sure what else could be going on here. Maybe someone has some suggestions??

 

[nebulous]

I'll check the water report. Good idea. Other than that I have no clue as to what's wrong. Thank you for the help

 

[nebulous]

Water report looks good. 54 ppb copper and chlorine is .67 ppm

 

[ktomminello]

You shouldn't have any chlorine or chlorides at all, imo it sounds like you have a stifled cycle- 40g can take upwards of 6 months to fully cycle....

 

[nebulous]

There is no ammonia or nitrites when I test the water. The chlorine reading was from a water report done by my city.

 

[Oceangirl]

you dose while filling, or throw the cap full of prime in and then turn on the water changer immediately?
The way I read it, you dose the tank, wait a while. then fill. You have to fill immediately.

 

[nebulous]

I've dosed while filling, dosed then filled immediately after and dosed then filled a few min afterwards. Each change was after deaths happened. Which is the proper way to dose. This was my initial thought as to the cause of the deaths as I am new to using the auto syphon system.

 

[Oceangirl]

I am new to it and the only thing I have lost is a baby java fern. It has to be a contaminate. Do you think your maybe over dosing and causing a PH drop? Can that happen?

 

[nebulous]

As my loach died day after being put in tank I'm thinking contaminate as we'll but what? Ph is the same before and after water changes

 

[jlk]

Maybe something got into your tank? Does anyone use aersol spray in its vicinity or carpet powder? Was it a new tank/filter or a used one? Maybe it was used & someone previously used something harsh in it such as CLR or Limeaway? Or they resealed it with antimildew type sealant? As your not having issues with the small tank even doing wcs with the aqueon, I have to wonder whats off in this one. Another thought is maybe an electrical short somewhere? Running through possiblities here...

 

[nebulous]

Filter is new. Bought with tank. No one has sprayed anything in room, I asked . I thought heater may have had a short in it so i replaced it last weekend. It was reading 1 to 3 ma when tested with a multimeter. I've done 2 massive water changes the last couple days, yesterday morning being the last time.

 

[librarygirl]

Odd, nothing really stands out to me here as a possible cause.

What you could do, just to see what happens, is go back to buckets for a while when doing water changes. When you add new fish, try a different supplier and drip acclimate. I doubt it's the Aqueon (I use one too) especially if you've used it on the betta tank without issue unless somehow something is bothering the fish from it that the betta tolerates but not sure what that would be.

As an aside, not related to the issues, but I'd also either get a second aquaclear filter (or upgrade to one large one, an AC110). A 50 gal filter on a 40 gal tank isn't much, I'd double it.

My best guess bad stock from the supplier, but until you get fish from somewhere else and see what happens then it's hard to say for sure.

 

[nebulous]

I thought about the stock too but his tanks look good, no dead fish clean. The aquion is the most likely culprit but I can't figure out why for the life of me. I'll start using buckets again Grrr and see what happens. Anything is worth a shot at this point.

 

[Oceangirl]

Where do you store your Water changer? Any possible chemical drip? Did you wash it in bleach? I lost a whole tank from fry, because a workman did something near the tank. Still don't know to this day

 

[nebulous]

It was in the laundry room next to the washer and dryer with the rest of my buckets and fish stuff Just found out it was kept there for a while. Normally it's in the bedroom closet.