Cuban gars and water hardiness

i'll do this rather crudely since my browser closed on me, deleting my very painstakingly typed post and i don't have the patience to type it out all over again. so do bear with this post.

early jan 2011:
removed a large piece of driftwood, cubans turn very light yellow bronze. readings as such
-- ammonia - 0
-- nitrites - 0
-- nitrates - 10ppm
-- pH - 7
-- I cant remember which reading was for which test exactly, but to the best of my memory KH (carbonatel hardness) and GH (general hardness) read 120ppm and 30ppm respectively.

29th jan:
cubans nice and yellow bronze

30th jan:
30% wc + add the driftwood back into the tank. cubans turned dark.

31st jan:
-- ammonia - 0
-- nitrites - 0
-- nitrates - 10ppm
-- pH - 7.5
-- KH - 120
-- GH - 180

any idea what's going on? my 2 theories are:

1) increase in water hardiness, for obvious reasons. my question here is, do you guys know if the hardiness of the water has a big effect on cubans? as far as i can remember we've never touched on that. the pH in my area is pretty high so i'm guessing that's how the pH/hardiness got knocked out of balance

2) adding the wood causes the tank to seem darker, blocking 20-30% of the light substrate from view. i've noticed that the general takn surroundings does have an effect on how "gold" the cubans are able to get; dark surroundings usually mean that the cubans cannot get that really light colouring that i like.

i don't think the upward swing in pH did it as i've never seen my cubans react adversely to upward swinging pH and i've had them in 7.7pH prior to this with them being yellow as can be.

thanks in advance, sorry for the crudely formed post!

MonsterMinis;4845438; said:

I'll take a stab at it and say it's the tannins from the driftwood. the water it'self is overall murkier. I've seen alot of fish do this. My florida gars are kept ina fairly light colored tank ( no backgound, barebottom, a few peices of white PVC, and a nice peice of driftwood) and they get some very nice darker coloring to them. where I often times see pics of them washed out in similar set-ups and at the store. The tannins don't bother me so sometimes it deffinately look slike "tea" and imo thats when they're spots really come out, and the overall depth of their colors show.

I'm sure someone will step-up with some actual scientific info or similar. But my own experiances I think it's the tannins themselves, or the dilution of the clearness of the water by them.

Click to expand...

thanks for your input. now i'm pretty interested to find out if tannis/softwater has anything to do with gar husdantry, i think it's not something sol or richard have mentioned. at least, not to the best of my memory.

E_americanus;4846434; said:

i'm at the office now so this will be short, but we have touched on this with Cubans in random panic posts about Cuban death before (mainly about 4-5 years ago).

- first off, it's water hardness
- softwater generally has less buffering capacity and therefore can give way to larger potential for pH fluctuations, etc.
- adding driftwood to water can usually lower the pH, lower pH also has a lower buffering capacity.

- from what we know of Cubans, often from some tough/fatal lessons, they are highly susceptible to fluctuations in pH, not necessarily a set pH or direction of pH. so their color shift could very well be responding to subtle changes in pH and the associated changes in water quality.

if it is just their color any everything else seems ok, then don't be too alarmed, but i would keep tabs on it. in general, having a substrate with high buffering capacity seems to work best with Cubans (or having some other way of maintaining consistent pH). i've had that in place with my tank using aragonite substrate (probably 80% of substrate is this compound, maybe more) and it has worked well with Cubans. at the same time, Richard and i have kept YOY Cubans and they didn't seem to respond as fatally to pH swings associated with water changes, feeding, etc. so there is still some mystery to it (since you are dealing with larger fish, i would ignore the YOY situation).

hope that helps for now--
--solomon

PS-- i'm sure Richard will respond with his observations/thoughts too--

Click to expand...

alright, the gars have recovered slightly (but not completly back to normal), and i think i feel safe in saying i'm not going to introduce driftwood to any tanks with cubans EVER again .

the current situation is that i removed the driftwood (IME these problems seem to stem only whenever i added dw into the tank) and changed the coral chips in the return section of the tank.

current reading of the tank is; ammonia-0,nitrite-0,nitrate-20,pH-7.5,KH-40,GH-120

the wood was used for a couple of months in my previous set up, but is huge. around 5' long and ~4kg. it is a seriously nice piece of wood though, and i'm pretty sad to see it go to waste. on the other hand, the cubans are definitely FAR more impt than some dw

thanks for the input Michael. the sump is probably a god sent (my tank is running on one eheim only) and i frequently find myself wishing i had more filter media space. i've been avioding the coral sand as it makes it nearly impossible to sift/clean. how to you get around that btw Sol?