Possible tank mates for african cichlids?

I got a 150 African cichlid tank with clown loaches, and a catfish. i got silica sand and smooth holey rock and a pH of 7.8 +/-0.2 Im looking for ideas for other fish to add. I'm looking for some odd or different fish to add, something interesting. So far here's my list of fish im interested in:
I DONT KNOW ALOT ABOUT THESE FISH SO IF YOU KNOW SOMETHING I DONT OR HAVE SOME OTHER FISH TO MY LIST. PLEASE ADD YOUR 2 CENTS.

Green spotted puffer (probably not due to ability to bite my fish in half)
Black rubber worm (probably not because it will escape)
Freshwater flounder (i know its brackish)
Monos
Glass fish (not dyed)
Some type of small eel(spiney eel)
Tea Cup Stingray or other small ray
red fiddler/gold claw crab.

HERE'S MY STOCK AS OF RIGHT NOW. ALL FISH ARE 1-4"
1-Cyphotilapia frontosa
1-Julidochromis marlieri
3-Cyrtocara Moorii
2-Copadochromis borleyi
1-Pseudotropheus crabro
1- Pseudotropheus sp. zebra
3- Pseudotropheus sp. acei
1-Pseudotropheus socolofi
3-Labidochromis careoleus
1-Metraclima lombordoi
1-Metraclima callianos
1-Melanochromis johanni
1-Nimbochromis venustus
1- OB Peacock
2-Clown Loach
1-Clown Pleco
1-Madtom Catfish
4- F. Betta
6-Apple Snails