Disaster DIY aka "How stupid could I be", kubo RIP

[bslindgren]

What's that saying again - if it aint broke - don't fix it!! Disaster DIY is a home reno show on TV where guys who thought they know what they are doing call in an expert to help. The quote is from a Sarah Maclaughlin song I have been humming ever since. So, what happened? Well, on another forum I was told that an air stone might remove CO2 and therefore be bad for plants. Made sense, so I bought a nice 600 gph powerhead (Hydor Korallia 2) and yesterday I made the switch. I also did a 25% water change at the same time. This morning my black neons spawned, so I was really pleased with myself. This evening I was admiring my tank when I noticed that my two silvertip tetras seemed to be working harder than normal for oxygen. I immediately checked the temperature, and to my horror it had gone up to about 30 degrees C - I'm not sure exactly because I was too shocked to register it properly. Then the real horror became apparent. One of my beatiful kubos was on its side - still alive but motionless. I quickly reduced the thermostat setting and replaced some water to get the temperature down. An hour later the disaster was complete. My kubo was dead. As I have indicated before, any loach is hard to come by where I live, so that's bad enough. But I have just killed one of my favourite fish by not thinking things through and monitoring the tank when I made some fairly significant changes.
My DIY CSI came up with the following. I had the heater thermostat set higher than I realized. The high setting was masked by air from the air stone bar continually chilling the water. When I took the air stone out AND added the power head, I had both the thermostat heater and the power head heating the water. Fortunately most of my fish seemed to cope, but the one kubo didn't. I know the other three kubos are stressed, but they seem to be fine, as are my clowns and the other fish (bushynose plecos and tetras). Anyway, I am not feeling so good about my changes anymore. Those kubos are my pride and joy, and now I have lost one. I feel like such an idiot......

[Diana]

[mikev]

Darn. Really sorry about this.

It looks like in this business the only way to learn is to make every possible mistake,....we all make them.

With loaches multiple air sources seem necessary.

[chefkeith]

Too many plants can suffocate fish also. At night plants use up oxygen and produce/release CO2 into the water. Because of this, many planted tank owners will put air pumps/stones on a timer, which will turn on when the lights go off. If this wasn't done the fish would be gasping for oxygen all night.

High levels of CO2 can also be an anesthetic (which puts the fish to sleep). If the duration of anesthesia is too long it will lead to euthanasia (death).

Many unexplained fish deaths are due to the lack of oxygen and CO2 build-up at night time. It's a very common accident. One of these days, anyone of us just might wake up, and out of the blue, we find out that fish are dead or look like they are dieing.

The only real way to constantly monitor CO2 build-up on a planted tank is with a pH controller. When the pH reaches it’s programmed low point because of CO2 build-up, the controller can turn on an air pump, which will raise the pH, get rid of excessive CO2, and add oxygen. When the pH raises past it’s programmed low point, the air pump turns off.

(Likewise, with these automated CO2 controlled systems, if the pH level raises past it’s programmed high point, it can allow CO2 to be pumped into the water.)

The higher heat drives down the oxygen content also.

[Mad Duff]

Like Mike said we seem to only really learn by our mistakes where fish keeping is concerned, I can appreciate your sense of loss after my recent difficulties

[bslindgren]

Thanks to you all for your support.

Too many plants can suffocate fish also. At night plants use up oxygen and produce/release CO2 into the water.

Thanks chefkeith. I don't have that many plants, but your point are well taken. Putting the airstone on a timer would be a good idea - one of the reasons I wanted to get rid of it was to prevent algae on the cover glass, which cut down on light, but if the air was only on for 5-6 hours every night, that should be less of a problem. I am pretty sure it was the temperature spike that did it in, though. As you stated, the oxygen decreases as water temperature goes up.

I seem to have lost two more kubos, since I have onl;y seen one of them today. I just turned the tank inside out looking for the other two (that is I looked in every hiding spot in the bog wood pieces where they liked to sleep), but I can't find them. This has affected the whole tank. The kubos were really quite unafraid and were always at the front. I think that made other fish less skittish. The remaining kubo is not at all as brave anymore, so all my loaches are hiding most of the time. Only the corys and the tetras are behaving normally. Who knows when I can get replacements - I haven't seen kubos in PG since March or so.

[crazy loaches]

Just wanted to point out something that isnt clear if you know or not. The use of airstone or other surface agitation promotes gas exhange between the tank water and atmosphere. This will drive out CO2 from the tank if your CO2 levels in your tank are artificially raised by something like pressurized CO2 injection. If you are not injecting CO2 than the airstone will actually help you by atleast trying to balance CO2 with its equilibrium point, and obviously O2 as well. Even with pressurized CO2 many still run a good amount of surface turbulence since they have been burnt in the past (myself included). Once you have the setup, CO2 is cheap, so running it a bit higher with surface agitation is no big deal. So to sum it up, if your not injecting CO2 in your tank then go ahead and run your airstone. Besides, with the very low CO2 levels in such a tank the CO2 would be quickly used up by the plants anyhow, the airstone would allow some small amount to be absorbed back into the tank.
Good luck.

[bslindgren]

Thanks Tristan. I am not that well versed in the ins and outs of CO2, but in retrospect, I think the problem was temperature. The thermostat heater seems to be working fine, so I think it was a combination of extra heating by the powerhead and the lack of cooling buy the airstone that spiked the temperature and drove down the O2. Unfortunately I didn't notice until it was too late. Anyway, I have now lowered the temperature a few degrees, and I have put a small airstone (I had a 10 inch bar) on a timer so that it comes on at night.
On the bright side, one more of my kubos has reappeared, although it's not a happy camper so far - I'm hoping for it to recover. Strangely, one of the kubos is completely normal (albeit a lot more skittish in the absence of its mates). The clowns and all my other fish (bushynose plecos, Corydoras sterbai, C. aeneus, black neons, and silvertip tetras) seem fine. I guess one has to be grateful for small blessings. It could have been a lot worse.
Thanks again for all the suggestions.

[crazy loaches]

Sounds good. It is a common 'misnomer' that you dont want surface agitation with plants. It should read you dont want excessive surface agitation with injected co2. Priority should always go to your fish even if you have a lot of plants (unless you only have plants). And even with injected tanks since co2 is cheap many run some surface turbulence regardless. But without co2 injection the only thing producing co2 is fish and thats not really going to reach levels high enough that a bubbler is going to off gas them (I dont think, though I have never experimented). No matter what you do if your not injecting co2 I highly doubt that the levels would reach over 5ppm or so, and by running a bubbler should be staying close to that. By injecting co2 most target 20-30ppm, which is unreachable without injection. So basically dont worry about co2 at all if your not injecting, its not going to make much a difference what you do. You could have no agitation or a waterfall, the only real difference is how much closer your fish may be to suffocating. Of course youre probably correct assuming it had a lot to do with the temp spike as that to will cause the water to hold less O2, but off hand I dont recall what the actual amount would be for that given tempeture change so I cant say for certain.

[bslindgren]

Miracle of miracles - my third remaining Botia kubotai has now re-appeared. One is still under the weather and was hanging around in the bubble stream of the air stone this morning. The other two appear to have escaped unscathed and were feeding more or less normally. I feel like I got away with one this time, although one of the three survisors isn't out of the woods quite yet, it appears. I'll have to see if I can get a few more to get them back to a happy little school - they are incredibly entertaining and attractive fish so it really hurt that it had to be one of them that suffered this fate.