Hi....I didn't have much luck with them (hatchets), despite great water parameters. They are very prone to ich. In addition, like some posts here on otos, some seemed to up and die without any reason. I bought a school of six and only one survived. I will admit tho', that, at the time, I wanted them very badly and they were new at the one place I got them. They may have still been stressed from travel. Some of them are listed as 'difficult' for caring for in some books and websites.
I will admit that they are truly top dwellers and they DO fly out of the water if scared. The post above is right. Be careful during feeding because that was the time they get spooked...when the fish dart for the food. They have an odd/unusual way of sorta motoring around just under the surface. Mine didn't touch flake at all and only would eat dried bloodworms. Didn't seem interested in frozen either.Sadly, I'll care for this one...maybe if some more come around to the lfs I'll try and get him some schoolers. But...I probably would stick with other top dwellers. There is an active thread here on the topic....danios are great. But...don't let my experience keep you from trying...that's what this place is all about. SH