Small tanks--20-29 (one of kind on each)
Yellow---midas blenny
reddish---fairy wrasse with caution. Too small a tank and this won't do.
blue---yellowtail damsel
quirky---pearly jawfish, tailspot blenny; small striped gobies; small-species clown
browser---not so useful in small tank.
Medium tanks: 30-75.
Yellow---yellow watchman
Reddish---(caution with coral: flame angel, coral beauty); firefish (jumps: use screen) hawkfish, with cautions.
Blue---yellowtail damsel still a good choice. Only one, up to 75 gallons.
quirky---jawfish and blenny still good bets; small-species clown pair
browser; starry blenny
changes color patterns very fast): you do need some algae for him.; algae blenny
100 gallon tanks:
Yellow---watchman still a good bet;
Gold---golden domino---shaped like a tang, bossy, dominant, maxes at about 5", and will run the tank; Do not combine with chromis, but otherwise they tend to ignore non-damsels unless the fish's swimming habit is wiggly or flitting. And they may wallow in nems or corals.
Black---black domino, ditto.
Also gold, various colors: clown pair can hold their own with damsels---they're damsels themselves. THe aggression level of maroon clowns and the dascycllus damsels (dominos, stripes, etc) is about the same. In the wild, multiple domino damsels host with magnifica nems, so that situation might be unpredictible with possessive clowns.
Red---various dwarf angels (caution with corals). Firefish too nervous for damsels.
Blue---Blue Fiji Devil; small number yellowtails; blue star damsel;
Black and white stripe---3 stripe dascyllus damsel; do not combine with chromis.
quirky---various jawfish (do not combine with damsels under 150 gallon), filefish, hawkfish, (one of kind); gobies;
browser---damsels do this; so will angels; so will algae blennies.
Yellow---midas blenny
reddish---fairy wrasse with caution. Too small a tank and this won't do.
blue---yellowtail damsel
quirky---pearly jawfish, tailspot blenny; small striped gobies; small-species clown
browser---not so useful in small tank.
Medium tanks: 30-75.
Yellow---yellow watchman
Reddish---(caution with coral: flame angel, coral beauty); firefish (jumps: use screen) hawkfish, with cautions.
Blue---yellowtail damsel still a good choice. Only one, up to 75 gallons.
quirky---jawfish and blenny still good bets; small-species clown pair
browser; starry blenny

100 gallon tanks:
Yellow---watchman still a good bet;
Gold---golden domino---shaped like a tang, bossy, dominant, maxes at about 5", and will run the tank; Do not combine with chromis, but otherwise they tend to ignore non-damsels unless the fish's swimming habit is wiggly or flitting. And they may wallow in nems or corals.
Black---black domino, ditto.
Also gold, various colors: clown pair can hold their own with damsels---they're damsels themselves. THe aggression level of maroon clowns and the dascycllus damsels (dominos, stripes, etc) is about the same. In the wild, multiple domino damsels host with magnifica nems, so that situation might be unpredictible with possessive clowns.
Red---various dwarf angels (caution with corals). Firefish too nervous for damsels.
Blue---Blue Fiji Devil; small number yellowtails; blue star damsel;
Black and white stripe---3 stripe dascyllus damsel; do not combine with chromis.
quirky---various jawfish (do not combine with damsels under 150 gallon), filefish, hawkfish, (one of kind); gobies;
browser---damsels do this; so will angels; so will algae blennies.