I have a new tank I recently set up (with a tank thread going here on the forums) and I have been trying to decide the best method of introducing fish.

I have heard over and over the "take it slow" advice, and I agree for the most part.  But i'm wondering if sometimes its better to throw that idea out the window and introduce fish on the same day in order to reduce their aggression against eachother.

The scenario I have is that I would like to have 3 tangs in this tank together, and 1 particularly aggressive flame angel.  I know they will be much nicer to each other if I add them to this tank all on the same day.  However, the tank is relatively new with a very small bio load at the moment and I don't want to trigger another cycle and cause any harm with a sudden ammonia spike.

The fish in question are:

1 medium sized yellow tang - about 10 years old

1 large flame angel - about 10 years old

2 yet undetermined tangs that I have yet to purchase.  I'm thinking a small blue hippo tang and a small purple tang.

What is the best way to handle this, all at once?  Or should I put the 2 little ones in first, and bring in the yellow and the flame angel later, since they are the biggest?

Its a 90 gallon tank with a 35 gallon sump with a refugium.  It was started with all dry rock and dry sand.  I waited a full 3 months for the cycle to complete before adding any fish or life (i used the dead shrimp method, along with some fish food in order to get the cycle started).

I have been testing my water often.  My numbers look pretty good, currently:

0 ammonia

0 nitrite

0 nitrate

400 ppm Calcium

7.5 Alk

0 phosphate

pH has been a bit low, fluctuating between 7.4 and 7.9.

 

You don't have much of a bioload at the moment, so if you do decide to do this with 3 tangs and an angel, I would be very careful and limit feeding for a while after addition to allow your bacteria to play catchup. 

You could also try to artificially increase your bioload by really feeding a ton right now prior to introducing new fish. This should increase amount of bacteria available in your system to balance the big increase in fish/bioload. 

Another idea, if you want any less aggressive fish, get them in now to make the tangs/angel addition less of a jump up at a later time. Just some thoughts. 

I agree with Adam.

How do public aquariums deal with 100's of fish crowded into a huge tank? They feed a ton and filter like crazy. They don't leave filtration to just biological filtration. I have noticed that Blue Hippo Tangs in a public aquarium are as fat as 2x4's.

You don't have to be a public aquarium or have a bucket of cash to filter like crazy, you can do it in a different way.

Biofiltration can be doubled, even quadrupled, without having to add equipment or a lot of established LR and LS. How? Add a large amount of Macroalgae to the display tank and a large amount of Macroalgae to a Refugium that is lighted 24/7. Then start feeding all that the new fish need. The fish will learn that there is plenty of food (aggression is 90% caused by the perception that there is not enough food). 

The large amount of Macroalgae will do three things:

1. Eat/reduce pollution like crazy;

2. Provide food for the fish; and

3. Provide cover for the fish

Finding a large amount of Macroalgae is not that difficult. People here are harvesting from their Refugiums all the time. A small amount of Macro can be grown into a large amount in as little 

as a month by feeding it fish food and making sure it has plenty of good light. 

As time goes by, the algae will be eaten, or can be harvested, allowing bacteria, bug and worm populations to increase, thus handling more and more of the biofiltration. After a couple months, the extra Macroalgae can gradually disappear as a food source, being replaced by food such as lettuce and Nori.

The power of algae to clean pollutants out of the water is sometimes misunderstood in this hobby. What I have described here really works well. I have done it dozens of times. 

At the same time as doing the above, I suggest learning how the fish, both old and new, can see you as the boss and learn not to boss each other. See this discussion (also listed in the Reefkeeping Tips):  http://utahreefs.com/forum/forum_posts.asp?TID=34014" rel="nofollow - http://utahreefs.com/forum/forum_posts.asp?TID=34014