Gymnogeophagus aren't a tropical genus, they are found further south so their native habitats get cool in the winter times. For health reasons, most Gymno (and Australoheros) keepers give their fish a 3 month period down to the low 60's F before bringing them back up to the mid 70's F for the rest of the year. This usually triggers breeding, and many of the Gymno species tend to get bloat when not given this cool down period. It also seems to drastically affect their life spans as well (ie much shorter without the cool down).
