The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Look at maybe a goby and pistol shrimp pair, or a blenny. Banggai cardinals are always nice when they get big they are able to eat bigger leftover pieces of food that smaller fish are unable to eat.
I have one with a clarkii, green clown goby, and a starry blenny. He gets along with all of them just fine, but I tried moving my rainford goby to that tank and he harassed the heck out of him. Never pays any attention to the shrimp/crabs.
I had a 6 line. Previously the only fish were 2 clowns and a goby which had been in the tank for a few months. There were numerous snails and crabs along with 2 peppermint shrimp.
I added the 6 line, 3 bangai cardinals and a firefish.
The 6 line was aggressive toward all the other fish but specifically the firefish even though at the store they were in the same tank. The firefish only lasted a day before I found it dead. But in that day the 6 line was constantly chasing.
The 6 line lasted a week before it decided to fight a power head and lost. I never saw the 6 line go after the shrimp but it was definitely aggressive. They are gorgeous but I won't add another one to a community tank.