Corydoras and PH

[DoubleDutch]

No offence but think you've got that wrong Stephen. A huge amount fish still is wild caught. Lots of Corys aren't (hardly) bred in capitivity (only by Vess hahaha). Vess mentioned earlier some bred ones indeed can be kept in more alkaline water than their wild brothers / sisters. What Ian meand to say lots of fish will survive some time in water with wrong parameters,  but will get health problems in the long term. Rams, cardinals for instance are bred like crazy, but still are having problems at high Ph and low temps. Reason : some bacteria won't get active / ugly at low Ph but will at higher Ph. Corys only living only 4 years isn't correct, but can be due to the wrong diet lots are given. At all forums i am active on that's main reason Corys get healthproblems / die. You could say they survive (poorly) at algaewafers for about 4 years. The longest / healthiest way to keep them : right parameters, right temps, right circumstances !!! Cheers Aad

[TropicalFishForums]

[Stephen]

I am always willing to learn ... 

[DoubleDutch]

I am too and still do hahaha !!! Right place to do so!

[plankton]

Yes, Aad's got the point there, I don't believe that sterbai will breed in a high ph, and the conditions have to be similar to the wild (vess will correct me if I'm totally wrong), so, although they may survive for a short time (2-5 years maybe) in a higher ph, they should reach ages of above 10, mainly nearer to 15-20 as should most corydoras, brochis and scleromystax. Aspidoras and the smaller dwarf corydoras may only reach around 10 years. So if anyone who has kept sterbai in a high ph for, say, 5 years and is happy with that, I would be bitterly disappointed, as I was when I lost mine at 9, although I had got them with no barbs and didn't expect full lifespans. (My ph is 7.0 by the way).
Hope that helps

[vess]

The problem is pretty simple. Corydoras are an amazonian fish. The ecological breakdown of their environment is 75% soft water lower ph and 25% wet season fluctuation. (Fluctuations in mainly temp, tds, kh/gh etc etc etc)

During peak wet season, ph can raise to 7.8 or so but the water seems to stay soft. Why? I really have no idea - the only reason I can give is that the water source is primarily higher ph and is crashing down many miles of amazon in a very short time. I read studies that showed ph of 7.4 at after heavy rain within 2 days it was 4.4 and back to 6.7 after more rain. All this was in the space of less than 3 days.

The fish have been shown to trigger when the ph drops after a fluctuation for example:

People hit cory with a cold water change and when the temp starts to climb and return to normal this is when they go. Why? Personally I think adding new water with slightly different parameters kh etc from the tap is an excellent trigger. When the temp returns to normal, the levels have stabilised and away they go.

My tap water is 7.0 out of the tap and is 6.4 within 24 hours. Therefor a water change.increases it and it falls when boosters wear off.

Boom... trigger.

My long winded point is this. Cory are a lower temp, soft water, lower ph fish. Will they tolerate higher parameters - of course, but they are not conditioned to tolerate them for long periods of time. I know there is a member on here that keeps panda in discus tanks and says they are fine - even breeding. This personally makes me bristle. Panda are known to breed even in high ammonia laced water. They have less of a sense of fry suitability than most other cory which is strange as panda are quite delicate. Keeping them in such high temp water is destroying this fish from the inside out because even tank bred species are not designed to take high temps for long. Sterbai for example are because the climate they live is a lot shallower hence the the temp is a lot higher. Have you seen c.harald schultzei? They look just like big sterbai and are also tolerant of high temperatures because its in the fishes genetic make up. Panda do not have this luxury.

Sterbai will tolerate higher temps happily but the water is still soft. I cant think of one cory that lives in higher ph for long. C.venezeulas is a subspecies of aeneus. The reason it is said to tolerate 7.8 is because the ph raises to that in the rainy season, but again this is 3 months put of 12. Would they toleratr it long term I personally doubt it.



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[Stephen]

Sterbai will tolerate higher temps happily but the water is still soft. I cant think of one cory that lives in higher ph for long. C.venezeulas is a subspecies of aeneus. The reason it is said to tolerate 7.8 is because the ph raises to that in the rainy season, but again this is 3 months put of 12. Would they toleratr it long term I personally doubt it.

Nicely put Vess.

Strangely even "Seriously Fish" have the Brochis splendens, which I previously mentioned, as suitable for water of pH 5.0-8.0, temp 20 – 28 °C and hardness of 36 – 268 ppm which goes against what you have just written so nicely; high pH, high temp and quite hard water. (link)
Then my reading of "Planet Cat Fish" (link) say the same as Seriously Fish.

All this information is confusing and somewhat conflicting with my other reading.
I think I will leave "catfish" to people who know much more than these websites, people like Vess.

[DoubleDutch]

Don't leave them but love them and learn about them from Vess (as I do every day).

[vess]

Sterbai will tolerate higher temps happily but the water is still soft. I cant think of one cory that lives in higher ph for long. C.venezeulas is a subspecies of aeneus. The reason it is said to tolerate 7.8 is because the ph raises to that in the rainy season, but again this is 3 months put of 12. Would they toleratr it long term I personally doubt it.

Nicely put Vess.

Strangely even "Seriously Fish" have the Brochis splendens, which I previously mentioned, as suitable for water of pH 5.0-8.0, temp 20 – 28 °C and hardness of 36 – 268 ppm which goes against what you have just written so nicely; high pH, high temp and quite hard water. (link)
Then my reading of "Planet Cat Fish" (link) say the same as Seriously Fish.

All this information is confusing and somewhat conflicting with my other reading.
I think I will leave "catfish" to people who know much more than these websites, people like Vess.

Brochis splendens are not Corydoras.

 While they have many many many identical traits and may well be joined by numerous cory in the upcoming catfish upheaval they also house a very tolerant immune system.

 Brochis never seem to ill!

Of course this is something I wont try and prove wrong as I am sure if the water is bad enough or diet poor enough they would suffer bacterial infections etc at some stage but based on the average cory (aeneus) for example their levels of recovery after cycle crashes, nitrite spikes etc really have to be admired.

One thing I will say is this based on the above discussion.

When the wild fish are exposed to higher ph one thing has changed. Thousands and millions of gallons of flowing water.

There is no chance for ammonia or nitrite to take hold which would be devastating to catfish at that ph. (As we know ammonia becomes almost defunct at lower ph levels) at ph 7.8 and abovr it would take just a trace of ammonia to cause a major weakening in the immune system of a corydoras.



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[charlieh]

Excellent answers, thanks so much everyone.

Taking all of your knowledge on board I shall just have to appreciate their beauty from the pictures that you fine people post on here. I won't be getting any if it means shortening their lifespan.

Ah well, there's plenty other beauts out there

[plankton]

I'm stickying this, there's lots of great info here

[Stephen]

8 months on from my posts in this thread and what a difference 8 months make.
I am now far more knowledgeable (more reading and researching).

Corydoras:
You need a more acidic to neutral water but will probably get away with a pH 7.4 or lower.
The corydoras are a soft water species (dGH 1-5) but will probably get away with a dGH 10.0 or lower.
Corydoras need a slightly cooler water 22-24 degrees would be ideal for most species.
A fully grown adult corydoras can be between 1.4 inches to 3.2 inches depending on species.
Brochis splendens (Emerald Bronchis) is not a corydora but looks similar to a corydora with similar water conditions and similar habits.

I now have 6 Corydoras sterbai, all are doing well.

[JoeNut]

I wish i had seen this thread sooner, i have just experiened the death of one of my two C.Trilineatus (3 lined cory)

It never seemed to grow from when i bought it, which was about 1 month ago. i wasn't aware up until now that they require a lower PH, mine is currently around 7.5 going off the test strip type of test kit.

My bronze cory's are thriving however, and the other one (3 lined) seems ok, although hasn't gained much size either.

If i drop the ph slighty by adding more bogwood (which seems to be a method online) could i increase the chances of the other surviving?

[flyingfish]

I have hard water and a ph of 8-8.5. I put 4 panda corys in my fully cycled tank and they all died within 4 days. I can't say for definite what killed them, but the fact is that I, regrettably, put them in wildly unsuited water conditions and I expect that had something to do with it.

[skyman114]

8 months on from my posts in this thread and what a difference 8 months make.
I am now far more knowledgeable (more reading and researching).

Corydoras:
You need a more acidic to neutral water but will probably get away with a pH 7.4 or lower.
The corydoras are a soft water species (dGH 1-5) but will probably get away with a dGH 10.0 or lower.
Corydoras need a slightly cooler water 22-24 degrees would be ideal for most species.
A fully grown adult corydoras can be between 1.4 inches to 3.2 inches depending on species.
Brochis splendens (Emerald Bronchis) is not a corydora but looks similar to a corydora with similar water conditions and similar habits.

I now have 6 Corydoras sterbai, all are doing well.

Moving on another 6 months ish Brochis splendens has now been re classified as Corydoras splendens:)

[Newbie fishkeeper]

I just thought I would add to this brilliant thread with some stuff I have been experiencing of late.
In my tank I have C. Venezuelanus and C. Splendens (formally Brochis Splendens). My tap water is around 8.0 and my tank water is 7.4 due to bogwood. Temperature 23-24c.
I recently went through some problems in the tank with resulted in a extreme nitrate spike and ph crashed to below 5. This resulted in the demise of quiet a few of my live bearers. As I got the problem under control the C. Venezuelanus have been spawning 2 days after the weekly wc and have never looked so good.

Take from this what you wish but it proves that the ph up temperature down does indeed trigger spawning.