I am sorry to day but yes they will become to big and cramped in a year. I suggest that you buy a bigger tank soon or return them to the fish store. You could also get someone to hold on to them for a year in there tank until you get you new one.
Hope this helps!
Good Luck!

Less than a year. They will literally kill each other if they are cramped. When they start fighting, maybe in 6-8 months, that is when you need to at least get a 20 or 30 gallon tank.

Grow too fast… and probably kill each other.

Also…. never buy ANY cichlid without knowing EXACTLY which species you are buying.Sounds like a Zebra (Metriaclima zebra) and Yellow Lab (Labidochromis sp.)… but could also be a female Zebra.Truth is,so many African Rift cichlid look alike at that size it is very hard to say what you have.
Anyway,the 7g is totally inappropriate… a 20g would be more appropriate now (and later).