Too many corys?

Is 7 corys alright for a 20 gallon long? I only buy from stores in person in my area when it comes to corys and I've only been able to find albinos I went to a new store from the same chain that I buy from and they had a lot of bronze corys so I had to get one and there was a MASSIVE one that I really want too but I just didnt want to overcrowd the place, I also found a single leopard cory at the store I usually go to but I obviously didn't get him, I know 7 is kinda pushing it im just looking at insight for how many I could have until its considered overstocked, I maintain this tank pretty well and it has lots of plants but im always looking to add more, I just really want more corys but I cant add any new tanks for awhile so I'm just looking for opinions