Lost two overnight, trying to figure out why (dead bichir pics inside)

MooseTheWizard

Plecostomus
MFK Member
Jan 22, 2017
106
145
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Canada
I lost two bichirs last night, both of which have been in a long established aquarium since July of this year. The other 3 bichirs in the tank are doing fine so far. I found them dead about 20 min ago.

Last night I did their normal ~70% water change, and fed the same food I always feed them (Hikari carnivore sinking pellets/algae wafers). I also wrung out the sponge prefilter.

I did 2 other aquariums water changes last night on different aquariums with bichir and haven't had any losses or different behaviour there.

The main suspect currently is some pothos I added to this tank yesterday. I did add it to my 125 a couple days prior with no ill effects, but the extra water volume could've diluted any chemicals enough to not cause an issue. I did thoroughly rinse the pothos before adding the roots/stem to the water, but maybe it was not enough. I've reached out to the plant provider to see if they use any chemicals on their plants as I did not find anything on their website.

I've included some photos of the dead fish. They had to have died sometime over night or this morning as I fed last night and they were all present. There was no smell, the water was still reading at 0/0/0 which makes sense as I had done a large WC the night before and the tank is heavily, heavily planted. The only markers I see on the fish is some bloody fins and around the anus, but in my experience this is common with recently deceased fish and I'm not sure if it's indicative of anything.

If anyone has any insights or ideas I am all ears. This is a pretty big blow for me, as I've had both these bichirs since they were pinkie sized.

Also I am aware the one is bloated, but the other is not so I am not sure if that could be related. He's been a bit thicker for awhile, as he's definitely the biggest eater and hits food before the others. Wasn't too worried as he was still growing, so the calories are going somewhere.

Anyway, any help is welcome - thank you.

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Potato Patatto

Dovii
MFK Member
Nov 11, 2020
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Did you rinse the sponge in the tank before you did that 70% water change? If so, you probably started a mini cycle by diluting so much. Other main suspects could be if you used a water condition, 70% water change is a lot. I actually saw a member here not more than a month ago lose a bichir that had the same red rash but on his back plus a few other fish. Everyone seemed to think it could’ve been an excess of chlorine in the tap water. Cities/towns frequently dose heavy amounts.
 
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MooseTheWizard

Plecostomus
MFK Member
Jan 22, 2017
106
145
51
Canada
Did you rinse the sponge in the tank before you did that 70% water change? If so, you probably started a mini cycle by diluting so much. Other main suspects could be if you used a water condition, 70% water change is a lot. I actually saw a member here not more than a month ago lose a bichir that had the same red rash but on his back plus a few other fish. Everyone seemed to think it could’ve been an excess of chlorine in the tap water. Cities/towns frequently dose heavy amounts.
Rinsing a prefilter is not going to cause a mini cycle, there's an entire canister on the other side. I also don't use water conditioner, I live on a well. As I said the water params here aren't the issue, at least not anything to do with nitrogen.
 
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Rayfishowner

Piranha
MFK Member
May 2, 2017
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Looks like chlorine burn to me. Did you city so any changes to well water? Sometimes they add extra chlorine to kill bacteria and what not. The redness is the reason why u believe so. The other issue may be ammonia burn. Maybe cleaning the filter and 70 percent was too much and there wasn’t enough beneficial bacteria to convert the fish poop into nitrates. I always do at most 50 percent on my tanks and rarely do 70 percent (unless I have an urgent issue).
 
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