breeding fish in planted tanks

[Dirk.Matthys at toyota-europe_com]

Hi all,

I keep a school of nine Crossocheilus Siamensis in my planted 70G community
tank . So far plants are growing VERY well in this medium to high  lit CO2
enriched tank and several fish species breed without effort. Some young
even grow up due to the dense plants cover.
I bought the C. Siamensis when they were rather small and due to the
abundance of food ( plants , algae and regular fish of course )
they have grown into decent size fish.The biggest one must be more than 3
inch now. Lovely fish, always seem to hang around in group scooping around
for food.
 Now, recently I started seeing some strange behaviour. On occasion they
seem to change colour pattern. It seems to be happening more after a water
change or after I add fertiliser to the tank( especially KNO3, figure that
out !)  !! The little black line that one usually sees around each scale
seems to become more dim giving the fish an almost "unhealthy appearance" .
The dark black line that usually goes from head to tail also becomes more
dim and looses contrast. Not that my fish  are unhealthy, on the contrary I
hope.  This only happens with  two fish at a time, and at those times the
fish that changed colours chase each other wildly through the tank. At
certain points they stop and start slowly circling around each other about
2 inch apart but very slowly with the heads pointed up. It looks like they
are sizing each other up.This circling can take from 5 seconds to  over a
minute , repeated several times within a frame of about 20 minutes. Then,
for no apparent reason they regain their colour and normal behaviour. I
have been looking around on the internet to find information on the social
behaviour of C. siamensis but I can't find decent info. ( identification
yes, but nothing about pecking order, territoriality, mating, no breeding
reports either ). Can anybody help me. Should I consider this behaviour as
fish showing off to establish a pecking order or could this be the start of
a mating ritual that gets interrupted somehow because the conditions are
not right? Does this behaviour sounds familiar to anybody? It clearly
deviates from their regular swimming, chasing food or chasing each other.
On a second note I like to add that this weekend I discovered baby
Megalomphodus Sweglesi ( red phantom tetra) in my Micranthenum M. carpet.
On the net it is considered a difficult fish to breed and raise but in my
planted tank it seems to work without any effort ( 2 babies only though,
but who knows what I find next month? ) If things continue like this I am a
happy man: Now I am a 100% supporter of the healthy plants= healthy fish
statement .
 ( tank specs and water : 70 G, temp= 25 Celsius, Kh 5-6 , DH 10-12 ,
controlled Ph 6.95, NO3 10-20 ppm, K ? , PO4 low to defficient, TMG for
traces + additional iron, sump filter with lots of pond filter foam only,
lights: 3X58 T8 during 12H + additional 2X 58 T8 about 6 Hrs, reflectors,
electronic ballasts )


Dirk