Oh no! Dead fish after PWC

[tabbycat0282]

I did a PWC on my active 5 gal after testing and found the water had a pH of 6.2 with Nitrates at 80 (all other values good). Recently, PWCs have been instituted so there is a bit of crap in the gravel. I stirred up the crap...dipped out ~2 gallons and added ~2 gallons of dechlorinated water (Pure used....have always used Pure). I did this last week and didn't have any problems. The only thing different from last week is that I replaced my filter (full) with a rinsed and swung cartrige. Oh yeah...the temp of my tank is 80 exactly (no heater just good light keeps it regulated...getting a small tank heater soon). I did the PWC 1 hour ago. I went to check the tank temp and found my glofish dead and floating in the tank. What could have happened? The glofish wasn't my favorite, but I hated to find it in that condition. Stumped and worried for my platy (my fav in the tank). I rechecked the parameters of the tank and found it to have Nitrates of 60 and pH of 6.5 ish. Upon examination of dead fish I noticed that his underside looked a little irritated. I wonder if he got caught in the current of the new water and injured. Has that ever happened to anyone else? Did I mention that I am bummed?

[Purrbox]

Those Nitrates are rather high. You need to up the percentage and/or frequency of your water changes. Nitrates should be kept under 40ppm. Higher levels could have contributed to the death directly or indirectly by making the fish susceptible to disease.

[meegosh]

Its always hard to say what causes a death if there are no symptoms that you can see. I agree with Joy though, those levels of nitrates are too high and can only cause problems. I would setup a PWC schedule and stick to it. It is the easiest way to make sure your tank and the inhabitants are happy Good luck and sorry for your loss.

[An t-iasg]

You mention that you put a rinsed cartridge in the filter. Was it an established cartridge - cultivated with the nitrifying bacteria? Or was it a new cartridge that you just rinsed before adding it to the filter? You don't mention an ammonia spike, but I'm thinking that if there was a small spike, that could have caused death quickly in a sensitive fish.

[tabbycat0282]

Purrbox & Meegosh: I know the nitrates are high, that was the main motivation for the PWC. Honestly the water change last night was the second change to happen since the tank was established >1 year ago (I was a bad hobbyist until recently). The 2 water changes (not just top-offs) were within a week of each other. The PWCs are going to happen more frequently now...no worries. Should I do the PWCs more often than once a week?

An t-iasg: I changed out the cartridge, but the gravel in the tank and the bio-wheel were always in the tank. I thought that would be enough to keep the good bacteria level in the tank.

I did fail to test the ammonia last night when I noticed the dead fish. Should I be worried about the acidic water conditions? I really need a 7 based on the preferences of the fish in the tank, but I can't seem to get there. Will doing the PWCs more often help keep the pH more neutral?

[Alaris]

Originally Posted by tabbycat0282

Should I be worried about the acidic water conditions? I really need a 7 based on the preferences of the fish in the tank, but I can't seem to get there. Will doing the PWCs more often help keep the pH more neutral?

No and no. Fish prefer a STABLE pH over an "ideal" pH. Do not condition your tank with pH up or down.
PWC's will not lower or neutralize your pH because your pH is based on your tap water. There are some non-chemical items you can add to your tank (like driftwood) that _may_ lower the pH a .1 or .2 or not affect it at all. I wouldn't worry or fiddle with your pH.

[meegosh]

As far as PWCs, I have been doing about 20% PWCs in my tanks every two weeks. In your case you might have to do two a week to get the nitrates back down to normal reading, but after that I would do every other week. As far as the filter media, I hardly ever change the filter media, I just rinse it off with some of the water I take out during the PWC process.

Most people at the LFS will tell you to change it every couple weeks or monthly but there is really no need unless it is deteriorating badly. They are just trying to sell you more stuff! I had the same polyfiber in my 10g for about 3 months before it started tearing apart and I decided to replace it. The key is to clean it off when you do your PWCs and it works just fine.

Like Alaris said, fish really prefer a stable pH. I wouldn't worry too much about it since you can't change it a whole lot. Hope it helps.

[tabbycat0282]

Thanks Alaris and Meegosh. I feel stupid....but glad to get the info on this. I have checked my water and it goes into my tank at a 7, but as I said before my pH is 6.2-ish. I will work on doing more PWCs to get the nitrates down and maybe that will help the pH more in a gradual manner. I have a 5 gal tank, so how much water is recommended to be changed at a time? I changed out 2 gals last night because I was upset with the nitrates (they hadn't changed from the other PWC that I did the week before).

Should I be stirring up all the crap that has built up in the gravel before I do my PWC? I can't figure out a way to vacuum my gravel (only 5 gal tank and have 2 plants) and thought that stirring up the gravel was the closet thing I could do get rid of the build up. I have a metal spoon that I use to move around the gravel enough to send the build-up flying then dip out the water.

Thanks for the feedback.

[bs6749]

Originally Posted by tabbycat0282

Thanks Alaris and Meegosh. I feel stupid....but glad to get the info on this. I have checked my water and it goes into my tank at a 7, but as I said before my pH is 6.2-ish. I will work on doing more PWCs to get the nitrates down and maybe that will help the pH more in a gradual manner. I have a 5 gal tank, so how much water is recommended to be changed at a time? I changed out 2 gals last night because I was upset with the nitrates (they hadn't changed from the other PWC that I did the week before).

Should I be stirring up all the crap that has built up in the gravel before I do my PWC? I can't figure out a way to vacuum my gravel (only 5 gal tank and have 2 plants) and thought that stirring up the gravel was the closet thing I could do get rid of the build up. I have a metal spoon that I use to move around the gravel enough to send the build-up flying then dip out the water.

Thanks for the feedback.

I have a feeling that you haven't tested the pure water that you've been adding to the tank. It doesn't always have a pH of 7.0. Actually you should be thrilled that you have a more acidic water as it lowers the amount of nitrates in your tank. Joy completed understated it when she said "those nitrates are rather high". I'd be embarrassed to have ANY of my tanks over 10 ppm. I highly doubt I have one that's over 5 ppm. 80ppm is certainly toxic to fish as is >40ppm.

Honestly, I'd recommend putting your gravel in a separate container, putting the inhabitants in their own container, and then dump ALL of the water out and start over. This time use half tap water and half pure water if you are insistent on using pure water. Is your tap water that bad BTW? Next gently rinse the gravel/substrate in water that's between 74-84 degrees to get rid of any excess wastes while maintaining the beneficial bacteria population. A clean 5 gallon bucket is excellent for this task. Put the rest of the stuff back in the tank and don't forget to rinse your filter!

[Purrbox]

I'd recommend picking up a Lee's Mini Self Starting Gravel Vac, it's the perfect size for performing water changes and gravel vaccing smaller aquariums.