Tank size will only be a problem if one of your sculpins is smaller than
about 40% of the body size of another, and spawning won't have anything to
do with it.
Sculpins have an exceptionately well-tuned system of lateral-line sensors
all over their head, and they rely on these to feed as much as they do
vision. It's worth noting that the largest pores are those at the tip of the
chin and at the front of the canal that runs right above the upper jaw.
These things are designed to sense minute movements of water and triangulate
exactly where the fish should strike.
I have had zero success getting them to take anything but live food, or
something that you actively move in front of them. It sounds like your guppy
factory should work fine. I used to use Gambusia to maintain sculpins, and
they worked great, especially if you keep the water in the sculpin tank
fairly shallow. Another alternative is to use their live food requirement as
an excuse to go out every week or so with a d-frame dip net and gather
stream inverts...
Mottled sculpins from Ohio should be able to handle temps into the low 70s
for short periods... the best study on thermal tolerance in sculpins to date
(Walsh et al. 1997) found that mottled sculpin from north Georgia had
minimal mortality when acclimated to 20 C (68 F) and withstood brief periods
of up to 33.8 C (almost 94 F!!) before losing equilibrium.
The guppies should be able to cope with water in the high 60s or low 70s,
but the rate of reproduction is going to drop dramatically, and since you
want nice fat sassy sculpins, you're probably better off keeping them at 78
F.
cheers,
Dave
Saint Louis, MO
--Walsh, S.J., D.C. Harney, and C.M. Timmerman. 1997. Variation in thermal tolerance and routine metabolism among spring- and stream- dwelling freshwater sculpins (Teleostei: Cottidae) of the southeastern United States. Ecology of Freshwater Fish 1997(6):84-94. offer! http://click.atdmt.com/AVE/go/onm00200359ave/direct/01/ /----------------------------------------------------------------------------- /"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 / nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word / subscribe, unsubscribe, or help in the body (not subject) of an email to / nanfa-request_at_aquaria.net. For a digest version, send the command to / nanfa-digest-request_at_aquaria.net instead. / For more information about NANFA, visit our web page, http://www.nanfa.org