With my guppy she was hanging out around the thermometer by her self. I knew by the way she was acting that she was close to having her babies. I put her in the breeding trap w/ a grate seperating her from the bottom. Within an hour she started having babies and all 15 survived in the trap for about 2 weeks. I then put a divider in my 55 gal tank and still have 9 that survived and are starting to get their color. I am still a newbie to fish and I just lucked into what I described above working for me.
Hope that helps,
Leigh