durable fish?

["Gordon L. Mc Lellan" <gordon2 at dimension-x_net>]

Thoughts about the durability of fish and plants... with a 
question or two in there somewhere

I live in Michigan, where it is cold at least 9 months out of the
year... cold is good and easy to deal with (just add heat).

However, on occasion, it likes to get hot here... really hot (for
us Northerners at least).

My fish don't seem to mind, or if they do, they're not showing it.

The past few weeks my tank's temperature has been swinging widely,
from 76-78 (heater kicks in below that) to 90 (highest recorded
water temp yet)... (outdoor daytime temps with lows in the upper
60's and highs in the lower 90's)  indoor temp is usually between
75 and 92.

The fish just swim around, eating, breeding (mollies seem to love
to make love) and eating.

When the temp goes off the scale on the aquarium thermometer, I
start adding ice (doesn't help much ... 29gal of water must take
a lot of energy to cool) ... although having fans blowing on the
water seemed actually more effective, but a little unsafe (had
one fall in a few times) ... no causalities but it really made a
mess, cleaning it's blades off in my nice clean water (12vdc fan).

Everywhere I look for information about mollies, platys, tetras
temps seem to fall in the range of 74 to 80.  Is the hotter 
water not hot enough to kill them, but increasing their metabolism,
therefore shortening their lifespan?

The plants well ... they don't do much, just sit there doing their
thing, but they're not all turning brown or whatever then do when
it's too hot... What do they show when it's too hot, or just die?

I moved all my fish to a new home, where they now live in a cold
basement ... and just in the nick of time ... when I returned
I found my old tank (which still had my plants in it) had gotten
up over 100 ... the anacharis didn't care for that and was all dead,
but the amazon swords and micro sword appeared not to mind and were
doing well.

Gordon