Nice, Caudo's are fun to work with. Your water is probably fine since it is from a well, they do prefer a higher pH and hard water. Watch your temperature, as these fish do better around 76 - 78 degrees. They like to eat plankton, mysis, krill, I think the freeze dried type is the best for them, along with a good cichlid staple flake or pellet should keep them happy. If you get a bigger tank you probably want to get 4 - 6 more as they do not get too large. However they do fine as a single fish too, they are a cave brooder and so this is why he is hanging out in the cave, he feels more secure there. I would suggest getting rid of the Chinese Algae eater they are really nasty fish, and will grow quickly and be able to beat up your Caudo. Then consider getting some small zebra danios, like 3 or 5. They will help your Caudo feel more secure and hopefully he will come out more.
They don't get too large, and they don't grow too fast, so you have plenty of time to make up your mind, as to whether keeping this fish as is, or getting a larger tank and try to work with a group.