30gallon Convict cichlid tank set up?

Question
Hi, I currently have a 30gallon fish tank set up with:

1 large cleaned natural terracotta pot (with the bottom broken out and sanded)
1 small yellow plastic plant
1 6inch rainbow japanese style "house" with 4 half inch by one inch openings (1 on each side)
1 Thermometer
About 1 inch of blue and white gravel
1 tank heater (Off, its for the winter)
1 under gravel aerator
1 clean presoaked 12" piece of driftwood that acts as a medium sized cave
1 55gal Aquaclear filter

In this tank I currently have one 4.5" pink convict cichlid. I believe it to be a male but im not absolutely sure. It does not have any dark colors on its belly.

Ive had this tank set up like this for a while and everything seems fine, but I would like to add a few more fish, for some color and movement into the tank. I was using aqaAdvisor and it said this set up would be ok:

1 convict cichlid
1 blue ram
5 tiger barbs

Opinions? Recommendations? I DO NOT WANT TO BREED CONVICTS, so NO female convicts.

Im looking to also add some more decor and hiding spots. I had a large plastic plant at one time but it fell apart in segments and was terrible. Any recommendations? I know convicts like to uproot and eat live plants :/ But my tank looks so boring right now lol
Im also adding a tank background. Last time it pissed my fish off so I took it down lol It was just an ocean scene. Should I just make him suck it up and deal with it, or forget it? He didn't loose color or anything, but kept angrily attacking the background. Eating habits and everything remained the same.

Also the aerator keeps coming out of the gravel. Apparently he LOVES to rearrange everything and moves all the gravel away from the aerator, causing it to float up. Which sucks for him cause he loves to swim though the bubbles. Should I add more gravel?

THANKS <3

Also I know this is silly, but how can I tell if my aqua buddy is happy or not? He swims around and picks at his gravel most of the day and follows me around the tank if I walk by. He's pink so he naturally doesn't have THAT vibrant of a color, but he doesn't look muted. His fins are long and flowy and his eyes look normal. Im assuming he's healthy (I keep the PH and ammonia levels in check as well as the temperature.) but I just want to be sure he's happy:)

Answer
Hi Ruby,
  From your description of his behavior, he sounds quite happy.  

  If you add any fish to that tank, you are going to have to add a LOT of plants; otherwise, your existing fish will rapidly eliminate the "newcomers" from HIS home.  I suspect that a ram will never be safe in there.  The barbs might be.  Another convict is not likely to be welcome either.  

  Definitely add a background, but don't put an ocean scene. Put something with green plants in it on the tank.  

-- Ron C.
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>