Update, another 2 eggs from adolfoi, may have interupted them in the act when cleaning tank , still happy tho.
Each species has its own preference re-temps, my heaters are removed for summer and the tanks sit at 24 deg.
Some sp like spawning in moss and long fake grass (think healthy dwarf sag size), others only lay on the glass or floating fake grass.
soft very clean water, very thin layer of soft sand on the bottom
3:1 m:f ratio is best and groups of min 5, ideally a dozen makes a good group.
Feed em well with quality sinking granuels & bloodworms every 2nd feed, mix in the odd white worm, afew 40% cold water changes (approx 4 deg lower than tank temp) or a low pressure weather front and if you are lucky presto eggs!
Some will spawn easy as other will show no inclination, NZ bred ones will go super easy, imported or wild caught, prepare to be patient. I have groups that spawn super regularly and others that wait months, some like my skunks simply dont spawn :evil:
batch sizes change from sp-sp as well.
HTH