Extiction level Event (Long)

[Dr Grant]

Very sad stuff happening in my fish tank. I had just recently did about a 40% water change and almost all my fish died. I'll give y'all the story and any input would be appreciated.

I started my 30 gal tank bout 3 months ago, did a fishless cycle and got some fish, some neon tetras, zebra danios, cory catfish, and a couple snails. On my first water change I lost a couple neons and it seemed like my fish would go into shock mode, non usual behavior. I tested my water and i figured this was because of a large ph change, something in my tank was dropping my ph. I took out a peice of driftwood, thought that was maybe doing it but it was still going down. The only other things in my tank are gravel, a couple plastic plants, and one fake decorative rock. I continued to do small changes (~ 4 gal) every other day or so to control my ph but this got taxing on me. My fish would still go into a shock mode for a short period of time but I didn't lose any. So i stopped doing this and the ph prol went to 6.4 or so.
For the past 2 weeks i've been giving tiny doses of AP's Ph up everyday or two to get to a good Ph to do a larger water change. Over those weeks i got it to 7.0 - 7.2, which is what my water is at. Did a water change, then said given event happened.

I tested the ph in the tank now and it's the same 7.0 -7.2. I don't think it has to do with the Ph but I figured i'd give you the story and let y'all decide about it. The temperature did go up maybe 6 degrees fahrenheit to 80 degrees. I checked the ammonia level and it was between .5 and 1.0 ppm.
My tank is cycled and my tap water test that much for ammonia also. So i don't think it's any of that.

I thought it was ph before but now i think it has to be something to do with the waterchange. I'm using Ap's stress coat as a de-chlorinator. Can that go bad early? It says it expires 1/08. It was probably sitting for a while unused, if that matters. The bucket I use used to have powder laundy detergent in it but i washed it real good and scrubbed it and also soaked it in hot water for a while. Could it be my water? I live in Minneapolis, fairly large city. I moved a lot of gravel around, could I have stirred something up?

They didn't all die right away, it took a while and hit some sooner than others. They would seem to lose their ability to swim how they wanted and turn over or not stay horizontal, and would then go on periodic erractic swimmings. I want to get more fish but I need ta have a good idea of whats going on before I do. Any input would be appreciated, thanks.

 

[Devilishturtles]

I'm sorry.

A few things. Are you dechlorinating the water before it goes in your tank? Are you making sure the temperature is correct and is not different? You said your tap has 1 ppm ammonia in it? Sounds like a tap water issue. When you tested your tap, how long was the water sitting before you tested? Try letting it sit out overnight and testing in the morning. This allows the water to get sufficient gas exchange.

Some people simply cannot use their tap water because of what goes in it to make it safe for us to drink. You may have to look into getting an alternate source. You can buy gallon jugs here for around 50 cents a piece.

HTH

 

[Hara]

It sounds to me as though you are losing fish due to shock from the change in water chemistry from the water change. It is imperative that you make sure the ph, the temperature are the same in your water change water as the main tank. The temperature going up 6 degrees instantly would do a number on your little fish.

If you feel there is a need for higher ph, try adding a power head for surface water agitation. Or if your tank has a closed lid, sometimes just keeping that open will help.

 

[RoK]

That ammonia reading could actually be because of chloramines.
What did you use to do the fishless cycle?

 

[jsoong]

Yes, most big cities use chloramines to disinfect the water. Add dechlor & it makes NH3 + Cl2. However, most dechlor will have binders to take care of that.

I suspect either a pH or a temp issue. Your water is soft & if the pH keeps dropping, you don't have enough buffer to keep a stable pH. I would suggest adding crush coral or another source of CO3 into your tank to up your KH to at least 3 to maintain a stable pH in the tank. Once you have a stable pH, then you can pretreat your change water with cc to that pH to avoid drastic changes. <Note that for small changes - say 5-10% - lots of people with cc don't bother to pretreat the change water .... but that's up to you.>

The other possibility is the 6 degree temp difference, although most fish will do fine with a temp increase ... it's sudden drops that kills them. To be safe, I usually match the temp and put the water in slowly (over 1/2 hr) to avoid any sudden swings.

The bucket is suspect too. I've read that you can never get rid of ALL traces of detergent from plastic. Also, a used bucket might have traces of pesticides or other nasties. You might consider a new bucket.

 

[Dr Grant]

I'm planning on tossing the bucket and the dechlorinator just in case. FYI, only my small fish died, all the cory's survived. I dunno what that means. Where can I get crushed coral or other things like it at?

 

[jsoong]

You can get crushed coral from your lfs. Alternative sources of CaCO3 would be crushed limestone, which might be available at landscaping place (you'll need to really wash well if you go non-lfs route). You can also use crushed oyster shells if you have a supply of that.

Basically, you add a cup or so of the cc into your tank (or filter). The cc will slowly dissolve in and raise the KH (and pH). It will stop at pH or 7.6 or so. As your HCO3 buffer is used up, more will dissolve in to keep the pH constant. This is as oppose to things like pH up, where the pH drops as soon as your added buffer is used, and you never get a stable pH.

CC is pretty foolproof. All you need to do is keep an eye on how much is left in the tank & add more as needed.