75 Gallon Tank... 6 Tiger Barbs And Now What?

I have a deep 75 gallon tank with lots of wood and plants. I put in 6 tiger barbs that school great as well as two rainbows (look beautiful) and a red fin shark. All was well so far as I got the chemistry down and then I added two Angels (yes, recommended by a very experienced fish store with the same owners for 30+ years). Day 1 no problems. Day 2, barbs picking on Angels. Day 3, one angel dead, the other hiding at the bottom of the tank in the weeds. Any suggestions for what else to add to a nice size tank? I was thinking of some combination of the following:
Roseline Sharks
Green Tiger Barb school
Cory Cats and clown loach or else an orange or blue crayfish

The only reason I mention the crayfish is that I used to have them and they were a lot of fun. Barbs seem to stay off the bottom. Only problems in the past were that when the crayfish grew out of his shell, I had a tank where the fish attacked and killed him. Figured with the big log in my tank he could hide out.

Any thoughts on the above or other recommendations? Silver Dollars?

 

Tiger barbs can be rather nippy. I'd suggest adding more barbs to the school. That way the focus is on the other barbs and not the other fish!

I believe Rainbows are schooling fish so more of those guys to keep them happy.

Clown loaches get too big for a 75 gallon so get cories!!! Although as the shark grows it can get territorial and cories don't care about personal space.

 

Definitely get more tiger barbs, whether it's the green or other color morphs around, I had 8 and re-homed them because they picked on my cories.

 

a group of atleast 10+ should be purchased when dealing with with Tiger Barbs.

Rainbow fish are schooling fish and need to be in 6+ groups.

75g is to small for clown loaches , they are schooling fish who need to be groups of 6+ and need a 125g at the bare minimum.

Crayfish shouldn't be housed with fish , they need their own tank.

 

75g is plenty of room for a considerably large colony of shrimp if you'd like a crustacean. Crawfish will kill almost any fish you have, they only do well with turtles from my experience. I add Cherry shrimp to every tank I can, they're colorful and easy to care for, plus it's hard for fish to pick on them because of their shell combined with their speed.

Clown loaches are a good idea for a larger tank, but a smaller Botiine species such as the zebra loach, yo-yo loach, or Polka dot loach would make good alternatives, none of them regularly exceed 5" at the very most. They do well in small schools, 4-6 fish will happily coexist. Loaches are likely a better alternative to cories, cories are easy to pick on.

I agree with everyone else, you need more barbs. I suggest a dozen total barbs so it's a considerably large school.

Just my opinion.