Since Kenyi only has one, a 10 gal will be fine for now.
Yeah, Kenyi... Pet Stores peeps are newbs, trust me on that :lol-sign:
There is no real general rule of how to sex them this early on, unless you
vent them. Venting can't really be done unless you have a confirmed male to compare to. You can also wait for them to color up, but that generally takes longer.
Anywho, Rob (my SO) actually got me into cichlids. I had talked of wanting a new hobby and he mentioned how cool they are. I looked into it, and bought my first Kenyi a few months later. I made the mistake of getting 4 kenyi's and putting them into a VERY (less than 5 gallons) tank together. Rob told me they would be fine... well, they all got killed by one of the males. I ended up getting a 30 gallon from a newspaper ad, and starting all over. A few months after that I asked Rob to get me a bigger tank for my birthday. I put my male Kenyi into the new 55 gallon tank, and he died a week or so later.
So, I started all over, re-cycled the water, and bought 4 red zebras and some yellow labs. A few months later, a good fish pal of mine decided to quit the cichlid biz, and gave me a whole slew of Cobues for a very cheap price. I've been doing them ever since