Fish stay at the top, don't eat, and die.

[Zankara]

I've been having a problem lately with my danios. They stop eating, hide in the top corner unmoving, and then die within a weeks time. I have lost 2 danios to this unknown problem, and i am in the process of losing another Danio and a very beloved male American Flagfish as well.
They fish try to eat for the first few days, but seem to spit most of it back out... On around day 4 they will stop eating all together. By how skinny they are at death, i would assume they die from lack of food rather than the sickness itself but i could be wrong.
Gills don't seem to be red or inflamed. I can't see any abnormalities on their body like ich or worms. They don't act as if their skin is irritated. They don't rub against anything. Simply float at the water's surface, uneating until death.


I do a 20% water change weekly.
I feed them once a day, normally around night (could overeating cause this problem?)
It is a 20 gallon tank with live plants.
Nitrates, Nitrites and Ammonia read as 0.
Temperature is at 75.
Tank is cycled.
PH was fluctuating between 7.2 and 7.8 so i thought that was the problem and i tried to treat it. Now PH is at 7.8 and 8.0. (Could this be too high, now?)
Tank members: a pair of Kribensis, 2 otos, 4 danios, 1 american flag fish, 1 apple snail.

I noticed that my kribs have started spawning and trying to raise fry. Which makes me think this is a parasite or disease rather than bad water quality.
At first i thought maybe the kribs protective behavior could cause fish stress, but this mysterious sickness has been going on for weeks now, and the kribs just only today took their fry out.
My other three danios, otos, and kribensis are acting perfectly fine.

Does anyone have any ideas as to what this could be?
I don't want to lose my flag fish, nor do i want this to spread to my beautiful Kribensis parents
Thank you for any help in advance....

[Sea-Agg2009]

Danio's like a lower pH, usually between 6.5 and 7. You should be good keeping the tank at or below 7.4 or so if you keep the pH constant. The constant fluctuation is a bigger problem though. The fish will be stressed out no matter what if the pH is fluctuating. Once you get the pH to settle out, you can be a couple of tenths away from optimal. The main thing is to keep it stable.

[Zankara]

I take it this fluctuation is what caused the Flagfish to act sick as well?

How could i prevent fluctuations?
I tested the KH and it's at 5dKH (89.5 ppm). Will this prevent further fluctuations? Is it too high? How could i lower the PH without dropping the KH, or am i completely missing what it is i should be doing?

[Georgia Peach]

when you do water changes, how much does the PH fluctuate?? Adding chemicals to change the PH in either direction usually creates a bigger mess than you are trying to correct. The best thing to so is to make sure all the fish you house can live within the natural parameters of your water.

[Zankara]

Flagfish, danios and Kribensis, from the sites i've researched into, all have the same PH parameters. I looked into this before purchasing the fish on multiple sites and asked the store employees as well.

The ph would change more from day to night than water changes. .5 at the most. I'd rather not use chemicals, but they look like my only option. I can't find much information on this.

Since ph fluxuation seems to be the problem, how can i fix this? Will adding or removing plants help?

[Maztachief]

What is the ph of your source water? If your tank was not fully cycled ammonia is a base and your filter may not be processing it quickly enough. Id imagine too that depending on your decorations such as shells or wood you might have something skewing the aquarium's ph. If the source water you're using is more along the parameters youre looking for I'd do a small 10% water change daily for like a week so that the ph is very gradually adjusted back to the source ph (which should be at least near neutral). The more differing the ph of your source water and that in your tank the more difficult it is to match them up and not have swings.

There is also a ph effect that I dont recall the name of that when you use ph altering chemicals causes the water to test correctly immediately after using them but then can swing back to your old ph, it has to do with the rate of chemical bonds occurring (acids are H+ ions zooming around that need to be grabbed by another molecule to be basic, OH-ions which come from bases grab the H and make H2O in an acid neutralization) , and the concentrations of the chemicals within the water. There may be an immediate lowered or raised reading as the chemical you added, acid or base, has not 100% reacted yet and so giving a few hours it may allow it to all react which all of a sudden can swing your ph which would hurt the fish.
Additionally there are buffering chemicals that grab H+'s and OH-'s that hold them as is and help keep the ph more stable.

Overall though, I'd do the water changes and adjust the ph that way before throwing chemicals at it. If it is still going wild, id start looking at decorations and see if they may be stuff like shells or certain rocks that can raise the ph. The other thought I had being that you mentioned a large day-night change is the plants. If you aren't aerating the tank much the plants will use up the O2 in the tank at night instead of making it (they need sunlight for photosynthesis and at night they metabolize sugars just like us and give of CO2 as they eat what they've made during the day, if you want you can google the processes). The reason soda is acidic is that it is carbonated and a reaction between the CO2 and H20 gives you H2CO3 which is carbonic acid. So, at night with dwindling O2 levels and if you have a bunch of plants with little aeration Id imagine the CO2 might jump a good amount and be stressing the fish and causing an acid ph swing, during the day the CO2 is being used and would leave less acid produced and cause the ph to go back up. Aerating allows for more gas exchange and due to chemicals at differing concentrations wanting to mix and be at equilibrium it would allow the CO2 to be less elevated in the water and more like the air outside the tank. Just my hypothesis though. Good luck!

[Maztachief]

Im sorry, the main acid in soda is phosphoric acid, but still CO2 can lower the ph in larger quantities. I did a little research and found that although some sparkling waters add other minerals for flavor which raises their ph a purely carbonated water will have a lower ph of near 5. As found in a random study on types of water given to chickens for differing eggshell qualities.

http://japr.highwire.org/cgi/reprint/1/2/194.pdf

But, like I said, just my hypothesis.

[Georgia Peach]

here is a pretty good article on buffering capacity of water (KH) - if your tank is measuring 5 - thats kinda low - a higher KH will make the water more resistant to PH swings

http://www.fishyou.com/water.php#pH

I use baking soda in my tank for buffer

[Zankara]

Maztachief,

First of all, WONDERFUL information. Thank you so much!
PH is normally 7.6, i believe. That or 7.4. If i wasn't running out of PH stuff i'd check for you right now. Tank is cycled, so no spikes or anything like that.
I've been doing small water changes daily. Ran a test of my water down at the LFS, and thats what he recommended.
I don't think it's any of the tank decor. All i have is bogwood, and terracotta pots. Pretty sure the terracotta is safe. I've boiled everything before putting it into the tank for good measure. Gravel is fine as well.

My tank does not have any aeration outside of the filter so perhaps i should look into an air stone?
As much as i don't want to add chemicals i may have to given that our water here is a little wack...


Georgia Peach,

Great article! Thank you for that. It's been tough finding information on this stuff.
Five is low? The fish store guy told me it was alright, but if it's low i'd definatly want it higher.
Is there any way for me to up the KH without upping the PH? My KH was orginally at 3 so i used Alkaline Buffer to get it to where it is now. However, that upped the PH.
Perhaps use less buffer during a water change?

[akangelfood]

Zankara, I'd definitely add an airstone if I were you. My first thought when I saw "fish staying at surface" was lack of air. Do they gasp when they're at the surface?

[Maztachief]

I just found some better evidence for the CO2 contribution to pH in an aquarium

http://www.hallman.org/plant/booth1.html
Look for :"QUESTION: How does one control pH with CO2?"

Additionally I looked I found a small blurb on it in one of my aquarium books that says it will screw with water chemistry if its too much. "Setting Up a Tropical Aquarium: Week-by-week" by Stuart Thraves. Its a pretty cool book I got for like 5 bucks.

Depending on what type of filter you have too it might not be moving the water around as much, air stones can help to get things moving in the tank as well. The smaller the bubbles the higher the surface area they have for gas exchange, so fine airstones are best. I use a bar one in the back of my ten gallon to move water up the back and down the front. and a disk just for fun under a decoration. Ive heard people say there is no such thing as too much aeration, which I'd agree with so long as it isnt overpowering the fish with too turbulent water flow. Also, placement of the air pump can be important as you dont want a siphon affect occurring if the pump is below water level, if you cannot place it somewhere above you should use an in-line check-valve that is basically one way and if the power goes out will not let water go back down the line into the pump. Also, the deeper the airstone or decoration the harder it is for the pump to push air through it due to water pressure so buying the minimum pump for your tank size is a bad idea. I usually also use a gang valve of some sort that allows flow control and splitting of the line for multiple in tank air things. Let us know how it all works out!

[emc7]

Five is low? The fish store guy told me it was alright, but if it's low i'd definatly want it higher.

Thats soft water. It means you have to careful with things that could move your pH. However, being toward the lower end of the scale doesn't necessarily mean you should change it. I think your snails would appreciate a higher kH, but your breeding kribs wouldn't. Small fluxuations in pH over time are well tolerated by riverine fish. Are you adding CO2? that can cause pH changes and can kill fish if over done.

I feed them once a day, normally around night (could overeating cause this problem?)

Yes, its possible. I have seen something like it with young angels and frozen bloodworms. A blocked intestine will cause a fish to stop eating and die.

[Zankara]

Getting an airstone as soon as i can. I doubt lack of air is the problem, but more C02 can't hurt.
They arn't gasping at the surface, and the other danios, kribs, and otos are just fine and don't act like they're having difficulty breathing at all.

Doing small water changes daily now.
Recording the PH and KH every morning and night in case of more fluctuation. So far i haven't noticed anything. The PH is dropping with the water changes no more than .2 a day, but so is the KH... which is frustrating me, because now i'm going back to square one with fluctuating ph again. Argh!

Thanks for the help so far, everyone.
I'll let you guys know of any new developments.

[Zankara]

The danio died last night.
Flag fish is still alive.

Found fuzzy stuff on one of my danio's mouths.
Looks like Columnaris.

Argh.
I might have to flush this guy... i'd rather not, he's been with me a long time... but if the whole tank gets infected....

[emc7]

Looks like Columnaris..if the whole tank gets infected...

Sorry to hear, this is a worse case scenario. My condolences.

[JustOneMore20]

Originally Posted by Zankara

Getting an airstone as soon as i can. I doubt lack of air is the problem, but more C02 can't hurt.

An airstone and air pump add oxygen to the water, not co2. If you have fish hanging out at the top, you definitely don't want more co2.


IMO a KH of 5 is just fine. Usually people say 3 and up should be fine to keep your pH stable. If its like 1 or 2, you want to add a buffer. I would use crushed coral or limestone rock to buffer and not a liquid alkaline buffer. With a KH of 5, I wouldn't mess with it.

[Buggy]

Wait.....way back there you said your ammonia, nitrites and NITRATES were at 0, right? A cycled tank with that many fish should be showing some nitrates even with plants. Could you check your nitrates again and post the reading?

[Zankara]

Nitrates are 0, unless i am that horrible at reading the colors.

Could something be messing with the reading? I've always gotten zero for nitrates.

[Buggy]

Are you using a liquid kit or dip strips?

[Zankara]

Liquid.

I'd take pictures for you but i dont' have a camera.
...i have a scanner though. Want me to scan it? XD