Yellowtail Blue Damselfish

Just one of these in the tank.  There used to be two... the second was the nastiest fish I've ever seen.  Hid in the rocks -- extremely territorial.

Scientific Name : Chrysiptera parasema
Common Names : Blue Yellowtail Damselfish, Goldtail Demoiselle
Yellowtailed Blue Damsel Care Level : Easy, good for saltwater beginners, but don't use them to cycle your tank. This is not needed with the use of live rock as the primary biological filter.
Life span : 4 - 6 years, possibly longer
Size : Up to 3 inches (8 cm)
pH : 8.1 - 8.4
Temperature : 75°F - 80°F (24°C - 27°C)
Specific Gravity : 1.020 - 1.025
Carbonate Hardness (dKH) : 8 - 12°
Origin / Habitat : Indo-Pacific
Temperament / Behavior : Much like other damsels, this one can be moderately aggressive. Aggression can be lessened or spread out if you have 3 to 7 in your aquarium.
Breeding / Mating / Reproduction : 
Tank Size : 30 gallon minimum
Compatible Tank Mates : Avoid keeping them in an aquarium with Lionfish, Snappers, Groupers, Triggers, Eels or any other predatory fish large enough to eat them.
Reef Tank Compatible? : They shouldn't bother the corals and/or anemones but can sometimes be little jerks to the other fish in a reef aquarium setup.
Fish Disease : Saltwater Fish Disease - Diagnose, Symptoms and Treatment
Diet / Fish Food : Omnivore - try to give them a variety of foods. They will take vitamin enriched flake foods, frozen and definitely live foods.
Tank Region : Middle to bottom
Gender : Difficult to determine

Three Stripe Damselfish

I have 6 of these in the tank at the moment.  They spent most of their time hiding in the rock for the first month.  Lately, they've been out and about more.

Scientific Name : Dascyllus aruanus
Common Names : Banded Humbug, Zebra Humbug, Domino Damselfish, White Tailed Damselfish
Damselfish Care Level : Easy, good for saltwater aquarium beginners, but don't use them to cycle your tank! Using live rock is currently one of the best ways to cycle a tank fishless.
Life span : 3 - 5 years, possibly longer
Size : Around 4 inches (10 cm)
pH : 8.1 - 8.4
Temperature : 75°F - 80°F (24°C - 27°C)
Specific Gravity : 1.020 - 1.025
Carbonate Hardness (dKH) : 8 - 12°
Origin / Habitat : From the Indo West Pacific and to South Japan.
Temperament / Behavior : Much like other damsels, this one can be aggressive and even more so as it matures. They may not tolerate other damselfish in the same tank and less aggressive tank mates may get bullied.
Breeding / Mating / Reproduction : Males form nests in the substrate and entice females to breed. Afterwards the males guard the eggs until they hatch and enter the water column.
Tank Size : 30 gallon minimum
Compatible Tank Mates : Avoid keeping them in an aquarium with Lionfish, Snappers, Groupers, Triggers, Eels or any other predatory fish large enough to eat them.
Reef Tank Compatible? : They shouldn't bother the corals, anemones and other invertebrates. Some have reported that they will nip at hermit crabs and shrimp species.
Fish Disease : Saltwater Fish Disease - Diagnose, Symptoms and Treatment - This is a fairly hardy species like many of the other damsels. Using damselfish to cycle a tank used to be one of the advised ways of cycling marine tanks.
Diet / Fish Food : Omnivore - they will do best with a variety of foods. Small marine origin meaty foods along with some herbivore rations will be good for them. Frequent small feedings everyday are advised.
Tank Region : Middle to bottom and usually near cover of some sort.
Gender : Difficult to determine from external features.

The Tank

The unattractive, in my opinion, coralline algae on the glass is, I hear, actually a sign of a fairly healthy tank.  That said, it'll be GONE by the next picture...

Unicorn Tang

This unicorn tang was one of the first fish added to the tank.  He's just about doubled in size over the last year.

Below is some care info on the fish:

Scientific Name : Naso unicornis
Common Names : Bluespine Unicornfish. Unicorn Tang
Care Level : Easy to Moderate, can be quite hardy once acclimated.
Size : Up to 24 inches (61 cm)
Life span : 10 years or longer
pH : 8.1 - 8.4
Temperature : 75°F - 82°F (25°C - 28°C)
Specific Gravity : 1.020 - 1.025
Carbonate Hardness (dKH) : 8 - 12°
Origin / Habitat : Indo-Pacific, Hawaii, Red Sea
Temperament / Behavior : They may be aggressive with other unicorns in smaller tanks but may do ok in multiples in extremely large tanks. They also are constantly on the move during the day and will need a larger tank for swimming space.
Breeding / Mating / Reproduction : Very difficult to breed in captivity.
Tank Size : 250 gallon (946 liters) minimum
Compatible Tank Mates : Avoid keeping them with other species of tangs.
Reef Tank Compatible? : This saltwater fish should do fine in a large reef aquarium.
Fish Disease : Saltwater Fish Disease - Diagnose, Symptoms and Treatment, always use a quarantine tank for your saltwater fish!
Diet / Fish Food : Primarily an herbivore and feeds on marine algae in the wild. Try to give them a variety of marine foods but predominantly marine algae and spirulina. Having plenty of live rock for them to graze on helps. They should accept vitamin enriched flake foods, frozen and live foods.
Tank Region : All over
Gender : Difficult to determine the differences between males and female unicorn tangs but in adult specimens the horn may be more pronounced in males.