So I have a 20g running as a frag QT tank for a bunch, well let's say I had fun with the WWC auctions and end of year discounts. It's to many to dip at once and drop in the tank so I figured I would setup the 20g, put a rack in it and let the coral sit there while I deal with them. I figured it would run for a few weeks tops. I built the rack, put the HOB filter on it, some rocks and two power heads to keep water moving. I needed some biospira. I always use this on setting up the temporary tank to kick start some bacteria. Maybe it helps, maybe it doesn't. I just do it. Being New year's day my options were limited so I ended up at Petco. So I am looking at thier tanks. Typical Petco, red cyano, green slime alge and aptasia everywhere. Then I spot this poor little yellow tang. He was so thin and gaunt I just couldn't take looking at him. No alge clip or food for him in the tank at all. So I took him home. The coral tank was already up and running so I figured I could at least get him fed and healthy and at worse give him to the local salt water fish store I trust. I have used this same tank for QT of other fish and will keep the water good for him and the coral. The positive is he started eating immediately when the seaweed clip was put in the tank. I have a very light load in my main 220g tank and would love to add him there when he is healthy. However, I already have a desjardini sailfin tang which is the same species as the yellow. The desjardini is also about 4x the size. What would be the best way to introduce him or shod I just not do it at all and send him off when he is good to go?