i talked to a friend about this last year and he told me he had bred them,what he told me he did was,he had a 2 foot tank,he taped a black binliner around it put a heater and a air pump in it bought 10 tetra from the shop put them in the tank and covered the top with black liner,he said he never looked at them for about 6 weeks apart from feeding them and he said he bred 100s,dont know how true or anything,as i wasnt really taken it in,i supose its worth a try. not my cup of tea,so i never botered,,good luck if you try it,,kenny