[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

antisocial plants and independent fish

There were two questions posted over the (US) holiday weekend that 
I don't want to see added to the list of QYNGA.  There's probably more, 
but these caught my attention.

Walter Wu wrote:

> Amano mentioned in his first book about "plants that do NOT get along
> with each other" - any ideas of these?  I know obviously certain plants
> require certain conditions that other plants can't tolerate well, but
> the way I read into it, it sounds actually 'agressive'.  Neil Frank once
> told me when I bought several pygmy chain swords from him that the
> narrow red ones he has aren't compatible with the broader ones - in his
> experience.

> Anyone have a list of plants that aren't compatible with others?

There was a thread on the list a while back (uh, a couple years back?) 
about allelopathy which is the suppression of plant growth by chemicals 
released by a nearby plant.  This is one phenomenon that might lead 
plants to not get along.  Another is head-to-head competition.  There's 
probably others.

I seem to recall that Vallisneria species and Sagittaria species were
incompatible because of allelopathy, but I don't know if there were any 
other similar pairs.

As far as competition is concerned, I think this is going to be dependent
on specific conditions.  

As an example... I have a nursery tank that contains (among other things)
Elodea densa.  I added a couple "dwarf lilies" (tiger lotus?) to the tank. 
The lilies started growing very quickly and the Elodea stopped growing
just as quickly.  The growth of other plants seemed to remain about the
same - but this is a real rough appraisal.  When I moved the lily to
another tank the Elodeo started growing again.  I didn't increase
fertilization when I added the new plants or decrease it when I moved
them, so the lilies took their nutrient needs out of the existing nutrient
"budget" in the tank, and the Elodea were the most evident losers. 

This kind of incompatibility can probably be fixed by using more or 
different fertilizer.

There must be other cases of allelopathic incompatibility, and probably 
hoards of examples where one plant out competed another.


Bain Chin wrote:

>I wonder if there are fish other than the black molly which you can leave
>in a tank without food. (The tank does have algae.)

>I believe that guppies are also in this catagory. I try it for a month, but
>the guppy seemed to have gotten thinner. (This question is related to a
>"perpetual tank." - a self sustaining tank.)

I've tried this with common guppies.  The population maintained for a 
while, but they stopped breeding.  Guppies don't have much of a life 
span, so the population dropped after a while and I started feeding.

Lots of primarily algae-eating or biofilm-eating fish (like otos) could
probably survive in an aquarium without feeding.  I can think of two
essentials:  1) You must have a small fish population and 2) the tank must
contain a diverse community of algae and potential prey.  Obviously, lots
of other blanks would need to be filled in, too.  This is something I'm
working very slowly toward. 

Adey and Loveland (1991.  Dynamic Aquaria, Academic Press) describe a
2,500 gallon, self sustaining freshwater "tank".  At that size the system
was actually able to maintain a fairly diverse fish population without
feeding, including several kinds of tetras, several kinds of catfish,
common livebearers and even a cichlid (butterfly ram).  Their book is a 
little short on the details. 

Roger Miller