Gravel and parasites

iis2see · Post by **iis2see** » 06 Dec 2005, 02:34

Does the the size and depth of gravel, affect the reproduction abilities of parasites that reproduce in it?
Do the parasites require dense confined breeding ground, or do they do best with some circulation of water.
I have coarse river gravel .25" < .5", about 1.5" deap, and wonder if reducing the depth and or using finer fill would reduce the spread of gravel born disease.

Post by **Janne** » 06 Dec 2005, 09:06

If you vacuumclean the gravel when you do the regulary water changes you will get rid of the problem, this happen only in substrate that lacks oxygene.
It's not parasites that cause this...it's bacteria that convert ammonium and nitrat but if the oxygen level are to low the process will be different, instead of nitrogen gas they produce sulphate/sulphur oxide (I am not sure on the word) that turns the gravel black.
Higher circulation helps a little and also to not overfeed your fishes.

Janne

MatsP · Post by **MatsP** » 06 Dec 2005, 10:46

Janne,

You're probably referring to Hydrogensulphide (VÃ¤tesulfid in swedish), SH2, which is a foul-smelling substance that is caused by (some)aneorobic bacteria.

--
Mats

Post by **Janne** » 06 Dec 2005, 20:30

Thanks Mats.

Janne

iis2see · Post by **iis2see** » 07 Dec 2005, 00:48

I don't have a problem, with gravel discolouration nor smell.
I am just wondering if there is a way to reduce the reproductive advantage of gravel, to fish parasites.

Post by **Janne** » 07 Dec 2005, 10:13

reduce the spread of gravel born disease.

I thought that was miscoloration you meant...gravel turns black but now when I read it again...I understand what you mean

Some parasites like ich use the substrate under the developement and if you have such problems it's important to vaccum the substrate because the medications that are used dont affect the cyst stage, the parasite leave the fish and reproduce...the cyst's are developing in the gravel and are protected with a shell and when they hatch they look for a new victim and when they do a medicine can have affect not before and not after only when they are free swimming. Bacteria's that can harm fishes thrives in a substrate with low oxygen level or if the normal bacteria level is very high.

Janne

MatsP · Post by **MatsP** » 09 Dec 2005, 13:05

I wouldn't have thought that thinner layer of substrate would make a significant difference to the reproductive cycle of for instance ich. Obviously, with more gravel, there's more volume for the cysts to be hidden within, but I wouldn't have thought that you'd get much difference once you've got more than a quarter inch or so of gravel, it's about the same whatever depth it is.

If someone knows of any evidence of the opposite, please feel free to comment.

--
Mats

iis2see · Post by **iis2see** » 09 Dec 2005, 19:24

Thanks.

I gather that there might be some advantage to the larger gravel, in that a deep layer of fine gravel may have a reduced level of circulation in the lower portions. The reduced circulation might provide a low oxygen content near the bottom portion of gravel, providing that unsafe bacteria, with a foothold.(?)

MatsP · Post by **MatsP** » 12 Dec 2005, 14:31

Yes, certainly deep layers of sand may cause anaerobic activity. A deep enough layer of gravel would obviously also do this.

Course gravel is less likely to be afflicted than fine, and obviously at some level fine gravel becomes sand and eventually fine sand...

--
Mats

Kana3 · Post by **Kana3** » 18 Dec 2005, 04:29

I have a small 1 by 2 tank, with maybe an inch and 1/4 of 4mm gravel. I've been guilty of not cleaning this for many months at a time, and I'm sure I may have even exceeded a year once or twice.

Now, when I have got around to siphon / vacuum, yes I get the old 'rotten egg gas'(VÃ¤tesulfid in swedish - thanks Mats!), but I've had the most magnificent plant growth in that tank.

And more importantly, no obvious indication of any bacterial or parasitical problems attributed to not cleaning the gravel. (please note the careful wording of that statement before you comment...and yes, I've had Ich, but only a fish here and there, never an outbreak). In fact, this is the tank my fish first began to spawn in - of their own accord.

Where I have a curiosity is, can you bury a parasitical cyst? eg: If they release whilst buried in gravel, can the free swimmers survive to make their way up into the open water? (would they even release if buried?)

Is it known how long these cyst's can remain dormant?