Both of these species are known to be good sand sifters, but I have seen some pros and cons with both. Sleeper gobies (depending on the species) are known to sometimes cover corals with sand, as they will pick sand up and drop it from the middle of the tank rather than sit on the bottom and sand sift. Diamond Gobies tend to be a bit more respectful of corals in the sand bed in my personal experience, but are more prone to jumping in lidless tanks. Sleeper gobies can also be a bit more bullyish too as they cover more swimming area in a tank then diamond gobies. All of this is just based in my opinion, I want to know other peoples thoughts on this as well though. I think each fish is suited to their own tank depending on what needs have to be met.
