Water Change Myth?

[Larry Bugg]

A very thorough , precise and informative response Larry.
TFS your experience with us .

Larry,

Thank you for your organized, detailed and well prepared post on this subject. I find it very refreshing that yours, and all of the other posts to the OP, are positive and helpful. Usually when the subject of why large water exchange is necessary, there are comments like "just make large water changes because that is what works and KISS (keep it simple stupid)". I happen to be one of those people that wants to know why, and I believe that understanding is one of the keys to success in life. For many years now, I have advocated that the primary reason for water changes and tank maintenance is to reduce the amount of organic compounds that pathogens feed on and thus reduce their numbers.

I would welcome your comments and thoughts on two my observations of your post:



Why not include all forms of pathogens, including bacteria, virus, parasites, and fungus?



My understanding is that there are less pathogens present in lower PH water and that most of them are completely different than those at a higher PH.

I would like to offer some additional information that may assist in understanding why discus require large water changes:

1) Many of the strains of discus available today have evolved in water with a low PH for thousands of years. As such their immune systems (which is determined by their DNA) have adapted to the quantity and types of pathogens (bacteria, viruses, and parasites, and fungus) that are common to their native habitat. It turns out that water with higher PH has not only many more pathogens, but also a different type. Thus fish that are kept at a higher PH are much more sensitive to attack from unfamiliar pathogens. Young discus are especially vulnerable because their immune system will develop and adapt as they age.

2) Another important consideration results because discus are quite sensitive and become easily stressed. Stress can be caused by changes in water parameters (PH, TDS, ammonia, nitrite, and nitrate), temperature, lighting, motion outside the tank, pecking order, and other factors. Water that is not biologically clean also causes stress. When discus become stressed, they often become lethargic and refuse to eat. When this happens, their immune system weakens and they are much more subject to attack from pathogens.

Paul

Filip, Paul - Thanks for the kind words!

Paul,
Bacteria is what comes to mind first. Your use of pathogens certainly fits the description MUCH better. I will definitely use that is other post. I also think that your points 1 and 2 take what I was trying to say and expands on it greatly. I think both of those points are a great follow up to my thoughts. I might borrow them also if you don't mind, lol.

I alluded to one of the reasons I feel it is necessary for us to go into some detail when giving advice. I strongly believe that people without experience about a subject really shouldn't be giving advice but unfortunately there are always going to be those who just have to be involved and are going to "pass on" the experience of others and give advice. Unfortunately they give partial info or info that deals with a slightly different situation and it leaves those who are looking for advice with bad advice. Hopefully if I give some detail with my answer my experience won't be passed on to others as "all discus need large daily water changes". This is why you won't find me giving advice when it comes to most medical issues with discus. I don't have the knowledge and experience to give advice so I leave it to others rather than trying to give advice based on others experiences. Ok, that's my rant.

[afriend]

Larry,

I also think that your points 1 and 2 take what I was trying to say and expands on it greatly. I think both of those points are a great follow up to my thoughts. I might borrow them also if you don't mind, lol.

Please, by all means, do so. Also, I have posted thoughts about this subject and others on my Homestead page, use those too if you find them helpful.

[brady]

I know this an old post but in Larry's post #5, there is 1 error.
The Amazon river empties into the Atlantic, not the Pacific.
Jay

[pastry]

Brady... I have a very similar problem.... if I see a tag sticking out of a stranger's shirt then I tell them (and a few dozen times when the don't know what I'm alerting them to, I just tuck the damn thing in)... I also will tell anyone (even a CEO of a publicly traded, billion $ company that the have a hanger... but I'm not touching it)... yet no one will tell me that my fly is down until the end of the day

Yep, if I saw that post then I would've done the same (5 years later). BUT... we now all get to bust vcd Larry's balls!!!