Sounds like way too small a meal for a 7 month old snake. As an example last night I fed my Coral Glow, who hatched on7/5/14 a small to medium sized mouse and he pounded it down no problem. His weight on 8/21 was 122g and I would guess he's already added at least another 10g's. (I usually only weigh them every couple of weeks.) I also have a Mojave that hatched on 8/4/14 and is currently 90 grams and she took a small mouse the other night too. So my youngest animal, the Mojave, has already moved beyond hoppers without issue. I agree with Eric, at 7 months your snake should easily be taking medium to large mice or small rats.