Two of my 7 S.A.E.s have taken to taken to chasing each other around.They
appear to be sucking the stripes off of each other.

Are they actually sucking on each other? Have you see it? If so, are you sure
they are true SAEs, and not CAEs? SAEs don't have sucker mouths.

After a bout of chase
and nip their stripes are barely discernable, but come back overnight.

That is normal for all kinds of fish in territorial disputes. The stripes fade
when they are fighting over pecking order. This happens with my clown loaches
as well as my SAEs. The color fading is natural and not harmful. And it's not
caused by sucking.

Am I
right in assuming this is a territorial dispute between them?

Yes. If they are true SAEs, they will probably settle down once a pecking
order is established. Especially with so many fish in the school. (The only
time I've had a real problem with SAE aggression was when I had only three of
them in a 29 gallon tank. The tank was too small, and so was the school. I
put the three SAEs into my bigger tank, and once they were with the larger
school there, there was no more aggression.)

What are their
reproductive habits and how does one sex them? These are about 2.75" long
( my original is now about 4.5") I am thinking about making one of the
aggressive pair go live with the guppies, but I wonder if they will eat the
fry.

I don't know if it's possible to sex them, aside from the usual assumption that
the fatter ones are females (if they are in breeding condition). They are
egg-scatters, and yours are a bit small for breeding. I have heard that they
are easiest to breed when young, but I've also heard that they aren't sexually
mature until they are 3" or so.


Leigh

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