NANFA-- Yawning darters?

Crail, Todd (
Tue, 26 Nov 2002 11:15:55 -0500

It's been nice to be able to turn my head every 20 minutes or so and see
native fish while I work. One piece of behavior I've noticed is with the
darters (I'm currently keeping Rainbow and Blackside). They do a "yawning
thing" long after a meal (most fish I *think* do this to purge anything out of
the gills at or near feeding time). I've seen walleye and perch do the same
thing at rest.

I wondered if anyone knew if this is to increase water flow/aeration over the
gills, like a barracuda "yawns" when they're at leisure?

Or is it suggestable they do this as a display? For example, the Austrl/PNG
rainbowfish I keep do a similar thing, but they do this whole head bobbing
thing. The blackside (if male) doesn't have anyone else to show off for,
unless it's into that inter-species kind of thing... ;) So I'm not really sure
this is the case.

Does anyone know any papers that have studied this? It would be interesting
to note if this is an adaptation that is normal or under stress, and if I'm
not supplying enough dissolved O2 :)

Thanks in advance!
I hope you know that this will go down on your permanent record.
/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
/ Association"
/ This is the discussion list of the North American Native Fishes Association
/ To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
/ For a digest version, send the command to
/ instead.
/ For more information about NANFA, visit our web page,