What I have learned is that actually, the larger a tank is, the easier it is to keep healthy. More water means a more stable environment- less dramatic temperature and condition swings.
I highly recommend that you cycle your tank with BioSpira. I used it and had wonderful results. I was able to stock my tank very quickly and my ammonia spike was really more of an ammonia blip.
If you are a beginning aquarist (like me), and you are planning to get a 35 gallon, I'd really encourage you to investigate dwarf cichlids like German Blue Rams, Bolivian Rams, or Keyhole Cichlids. They are less aggressive than many African Cichlids and stay small enough for a tank the size you're talking about.
I have german blue rams and I just love them. I find that they have a lot of personality and are very pretty. Another nice thing is that because they are not very aggressive, I can also keep community fish with them. I have diamond tetras, harlequin rasboras, a pleco, loach, and two types of shrimp (all in a 30 gallon tank).
Though not as colorful, Bolivian Rams are known to be hardier than GBRs, and grown a bit larger. The males have lovely long pointed fins tipped in bright red. I have seen some that are very striking.
Kribensis are another very attractive dwarf cichlid, though I've heard mixed feelings about how they are in community tanks.
If you do decide to get cichlids, it's very important that you match them with proper tankmates.....for example, yellow lab cichlids should probably be in a semi-aggressive, exclusively african cichlid tank.
As far as water conditions, that will depend on what kind of fish you pick. African Cichlids do well in relatively hard water with a high ph compared with South American Cichlids like rams.
When choosing tank shape, go with a longer, wider tank over a taller, narrower tank. It makes sense, there's more surface area on the bottom for hiding spots and most fish spend more time swimming back-and-forth than up-and-down.
Speaking of hiding spots.....it's really important to provide many. Cichlids are territorial (partially because of their responsible parenting behavior) and happy, healthy cichlids need hiding spots to stake out and claim as their own. You can do this with rocks, plants (or a combination of the two), driftwood (which you should know tends to lower the ph and make the water a little yellowish for a while), and also I've seen lovely tanks done with ceramic pots that have been cut in half and partially buried into gravel.
In terms of plants- I understand that sometimes cichlids like to tear them up....it's never been a problem for me, but I have little guys. I keep a lot of amazon swords in my tank (as they like low-lighting conditions). Plants are very good for the tank, as they clean out toxins, oxygenate the water, and provide more cover for your fish.
I've attached a few pictures of my tank to give you an idea of what it looks like and of what my rams looks like.
Good Luck!! Keep us informed!
