i bought silver mollies around sunday. a few days they have been in my 10 gallon tank. i have 2 of them along with 2 mystery snails. i noticed that everytime i go and look at the tank they always hide? is that bad? and as i look their gills move pretty fast. is it normal????? and can you give me tips on how to take care of silver hatchet fish and silver mollies thanks I: