Indeed, or even not so small fish as they can get close to a foot across! The species is Ophiarachna incrassata. I would prefer serpents myself, as there are too many stories of other species of brittles out there that have gone on the feed, too.
Also, when you're looking for scavengers, you really need to be careful of a few things, not the least of which is to ensure that they're really detritivores. If you have a relatively finely grained gravel/sand bed, then Archaster typicus might be a good choice. Unless you have a very large system I would start with only one.