Thanks. Things have improved considerably. I've only seen one inhabitant
scratch lately, a bala shark, and not often. Either I was neurotic (not
unlikely) or it was something temporary (perhaps a water condition?).

I'm almost positive after looking at the photos at planetcatfish that they
are true otocinclus, although I can't say which one. I haven't seen an
"attack" again either.

thanks to everyone who helped,

bob


"Sabine Haller" wrote in message
...
If your fish are scratching all the time, then you most propably have a
parasite. If they are scratching occasionally (once in a while) , then
they
just have an itch and nothing to worry about.

If your fish are scratching regulary and your Otos "attack" them, I would
certainly get my magnifying glass out. Sounds like you do have a parasite
and the Otos might just be after them.

We have several different versions of Otos and Paraotos, none ever attack
the fish or suck on them. Otos tend to do better in groups, my Paraoto
killed of all his mates, so he is now in a little tank where there is only
space for one Oto anyway. Paraotos seem to be more active during the night
as well (I used to think I lost him several times, as I couldn't find him
in
a 5G tank for up to 3 weeks, but then suddenly he would re-appear and hang
on the front glass...).

You can find "your" species he

http://www.planetcatfish.com/core/index.htm

(click on cat e-log)

Greetings
Sabine