Adding chromis to a 75g tank

Hi, newbie here. I've got a 4 month old 75g tank c 20g sump, 110 lbs live rock, 2 fire shrimp, 8 snails (turbos, cerith, and a cowrie), 2 hermits, and now a lawnmower blenny just out of quarantine. ammonia, no2, no3 are all 0. Still have brown algae, but its decreasing and the coralline algea is begining to layer on a couple rocks.

i'd like to add blue chromis. my thinking is they're colorful and active, and sound like they're pretty durable and a good beginner fish. I'll plan on quarantining them for at least a few weeks. My questions are - (1) how many should do well in a 75g setup, (2) how do you do quarantine with a group of, i'm guessing, 5 or so fish, (3) how do you feed these fish - my shrimps eat out of my hand when i feed nori or flakes to supplement algae?

TIA- any additional advice is greatly appreciated!

 

well every one would agree that 1 inch of fish per 5 gallons of water but green /blue chromis is not a very big fish ( keep in mind they can grow and fatten up to bout 3 inches )
I my self have push this to near 1 inch of fish per 10 gallons.

If you want blue's I would suggest putting them in last , they are little war mongers.
and will establish a territory real quick and any thing added after that will have a hard time finding it's own space.
Blue meaning (dark blue)

*Mission* up there provided a pic which i usealy call a green chromis and they are the easier of all the damsels and don't carry on a territory war like the other of the damsels.

 

wildreef and mission, thanks for the help. i thought that chromis were unique to the damselfish group and much less aggressive/territorial? are blue chromis less problem than blue damsels, or should i think about just putting in green chromis?

again, tia.

 

Ive had a few of these guys, never a problem with them picking on any of the other fish in the reef.