What's Your Biggest Water Change Mistake?

[HH Morant]

My biggest water change mistake was this past Friday when I changed the water on my 10-gallon quarantine tank containing 5 young angels. The tank is near the sink in my kitchen, so I use a 2-quart plastic container to bail the water out of the tank and into the sink. Midway through the water change I noticed there were only four angels in the tank. I double-checked - just four. I must have poured one down the drain!

I frantically reached down the drain and after a little searching I felt the fish flopping around down there. He came to rest on top of the garbage disposal. I was able to catch his top-fin between two fingers and lift him out. I quickly put him back in the tank.

Now I am not even sure which one it was. They all seem fine. That was close.

Below is a video taken afterwards.

So what is your memorable water change mistake?

 

[lefty o]

ive been fortunate, and as of yet, i have never had a water change disaster.

[Jawjagrrl]

How fortunate that you had a garbage disposal and were using that sink, sad to consider the outcome otherwise 😞 Glad it all worked out.

I've definitely made my share of fishkeeping mistakes, but the water changes haven't been one for me personally. I can relate something that happened to my stepkids when they were little though.

They wanted a betta, and their mom set up a big vase/bowl/snifter with a peace lily aquaponic setup in their kitchen shortly before their older half sister was coming for a visit. Something triggered a desire to do a water change, not sure what. Big sister was trying to be helpful, saw the water didn't look good (I doubt this had cycled) and so she put the betta in a glass, dumped ALL the water and replaced with water out of the tap, immediately returned the betta to the bowl.

It was municipal water. There was a sad little fish funeral in the powder room shortly afterwards. The bowl was still in with my husband's things when we met years later.

[Jennifer V]

My wife was changing the water in our 10g and accidentally added Fritz Complete to the tank instead of Fritz Zyme 7. Shortly after, all the poor peas were gasping at the top of the tank. I quickly checked the water parameters and all was fine, with the exception of the fact that nitrates were extremely low for the tank. Then we realized what happened and we did an immediate second water change. Everyone came out unscathed, except the two of us, who cried because we were so upset we hurt our precious peas. 😆

[Andy's Fish Den]

I've overflowed a couple tanks, but thankfully my fish room and all but one of my tanks is in the basement with concrete floor. Other than that, one day I was doing water changes on all my tanks (~25) and I didn't realize that the pilot for my water heater was out, so it never kicked on to heat. I had set the temp when I started filling tanks, I drain all the tanks first, then start filling them up. By the time I got about 3/4 of way through filling tanks, I happened to stick my fingers in the water going into the tank and it was cold, I ended up having to light the pilot and wait a half hour or so until there was hot water to mix. No fish were harmed, thankfully there was only two or three tanks that were colder than should have been.

[MickS77]

When I was younger and still living at home, overflowed the bathroom sink using a Python...on the second floor. Water spot on the kitchen ceiling below. My Mom and I fixed it and didn't tell my Dad until a few years later 😄

Edited March 8, 2022 by MickS77

[Bev C]

I have to many to count 😆🤭  

1: My Mom has a habit of stopping by the day  of my weekly water change  I discard tank water with a pump and hoses and usually stay there to watch it but i got distracted by Mom and forgot to take hose out of tank i had the pump off but it still drains if hose is in the water thank goodness i did  not drain my tank completely dry  pretty close though 

2 : canister filter stop working when i turn it off to clean ,, there was a a small part broken  ,, had a warranty called the company they was out of the part and could not make it During Covid lockdown and a storage of plastic  they could not make the part due to not having plastics ,, we searched everywhere on Amazon  and etc for the part with no luck finding it they put me on the list ,, I had wait 5 months  for that small part for the canister ,, Thank goodness i had a backup  Aqua Clear hang back filter  and two sponge filters that i used till i got the part ,, 

 

[Cinnebuns]

This isn't mine but a friend's from when she was younger that she likes to tell. So her mom always did the water changes but it was the 1 year anniversary of getting the fish, so to celebrate she decided to change the water. She took the fish out, took the water out, scrubbed everything clean (she obv didn't know about beneficial bacteria or partial changes).  Then she put the water in, put the fish in....then poured in all the gravel. 

Anniversary day was a sad day. 

[Guppysnail]

My biggest was filling my 5 gallon stainless steel pot that heats my water to heat my pretreated water at the sink with a python hook. I turned it on and went to check on a tank that was refilling. I got distracted by something the fish were doing and completely forgot about it. I flooded the kitchen, dining room and the laundry room in the basement. 
I also had a similar situation as you @HH Morant I was keeping zebra danio I struggled like crazy to catch when I wanted to they are fast.   I was scooping out water for a water change with one of the disposable red drink cups into a bucket. As I dumped it in a utility sink I watched the zebra danio swim down the drain. I was not fast enough to catch it. 

[Tanked]

Thankfully, my biggest mistake so far has been accidently letting the frayed edge of a hand towel come into contact the water surface after refilling the tank. 

While I tended to other things, the towel began soaking up water. When the water reached the top of the rim, it began to  syphon water out of the tank. When I went down to the basement later, I found water dripping out of the ceilings and running across the floor. 

[TheChosenOne]

Other being on the verge of nearly overflowing my tank a dozen times. When I was younger and originally int he hobby I remember forgetting all about the temperature of the water I was putting back into the tank.  I recall going back over to the tank to wipe up and feeling the glass and it was cold to the touch...very cold. I quickly drained the tank again and added warmer water.  I didn't even have a means of temperature matching my water back then I just did my best by touch.   Luckily, I most kept Zebra Danios and common pleco that I had no business owning. ( I mentioned I was young). All the fish survived the momentary exposure but I made sure to never do that again.  These days now that I’m back in the hobby and much older, I use a temp gun to match the temp at the faucet before it ever hits my tank.

[Widgets]

My biggest water change mistake was back in my early days. As a kid I kept wild caught native fish in an tank on a picnic table under a tree in the back yard. They never really got any water changes, and often were overflowing with rainwater, nature's water change. When I got my first tropical tank I didn't know about water changes, so I didn't do any.

[Dawn T]

My biggest water change mistake was in the very early days of fishkeeping for me. I did constant, severe water changes (to get rid of that cloudiness that pops up early on) and kept disrupting the nitrogen cycle desperately trying to establish itself. Thankfully, another hobbyist heard me talking to pet store staff (who advised even MORE water changes) and told me to leave it alone. He explained the basics of the nitrogen cycle. I chose to listen to him. End of problem within very short order, of course.

[skipper]

Lol just this evening… when I use the python on my kitchen sink for some reason the brass adapter always locks on to the faucet tighter then the green plastic connector and I inevitably use channel locks around a wad of paper towels to pry it off. Bored of this, tonight I lightly tightened. Filled my 55g, turned the water off at the faucet. Filled my 15g (which I don’t walk away from), flipped the switch near the siphon, prompt spewing explosion at the sink. Channel locks it is…

[Kathy F]

My son's glofish tank has a super red longfin pleco.   His tank also has pirate ship decor that is hollow for fish to hide.     While I was changing the water I took the ship out of the tank to scrub some algae off.  I gave it a few shakes under water and the corydoras swam out.   Then I rested the ship on the edge of the tank for a few minutes while I did some other things.   Then brought it to the sink to scrub the algae off imagine my surprise when the pleco fell out.   Wosrt part he didn't fall into the sink he fell out just as I was about to place it on the counter, so he fell 3 feet on to a hard laminate floor.   He survived without water for a few minutes and the fall but I felt terrible for the poor thing.   I'm pretty sure the pleco is traumatized because he won't go near the pirate ship anymore.  He either hides in the cholla wood or behind the UGF uplift tubes.