You should get the 2 convicts or a group 4 of electric yellows not both,it is best not to mix African and American cichlids.

I would reccommend only putting 1 Male Cichlid and at least 2 females in 1 tank no matter what the size is. Cichlids are very territorial and will kill other cichlids. If you plan on putting non-cichlids in the tank as well i would reccommend a school (more than 5) of very fast fish! The Cichlids will chase them so they need to be quick or they will be dead! I have had fish tanks my whole life and have learned from experience. Good luck on your tanks! By the way, if this is a new tank run the water alone in the tank for at least 7 days to get the bacteria levels where they should be.

Electric yellows and convict cichlids both have different needs especially in regards to water parameters. The yellows need pH 8.0+, hard water,etc. while convicts need softer water since they come from rivers and lakes in central america.
With that covered, do no tmix the two species.

Also if you end up with a pair of convicts, they will pretty much kill anything in the tank that they assume to be a threat or cichlid if they do start to spawn, which will likely happen if you initially acquire a pair.
(btw: you can’t just put a male and female convict and expect them to pair up. you have to actually look for a pair. otherwise you’ll have the male killing the female or vice versa. it’s happened to me 3x.)

As for electric yellows, you will need a male with a ratio of 2-3 and even 4 females. With that in mind, in a 30 gallon tank i think it might be best for you to choose the convict.

You could still place the yellow labs in there since they are relatively more docile than other mbunas but please do not mix them with convicts or you’ll end up with dtorn fins and stressed fish. Go for either or. Good luck on your choice!

Convicts and Electric Yellows are not dwarf cichlids. If you wish to have there fish, it would be best to only get 2 of each so there wouldn’t be any competition for food and space.