Damsel help

[Coats]

I've had a 5.5g tank up and running for about 3 weeks now that I was going to use as a QT tank while I'm building my 20g nano tank. This past weekend I added a yellow tail damsel to the tank to hang out so by the time the 20g was ready to cycling I could just add him to the tank. The 5.5g parameters were pH: 8.2, 0ppm ammonia, 0ppm nitrate, and 0ppm nitrite, with 1.025 salanity. The damsel ate well that night and swam around the tank just fine. The past day or two I haven't been able to get him to eat nor has he been moving around in the tank all that much. I checked the parameters this morning and got pH: 7.6, 0ppm ammonia, 0.25ppm nitrate, and 0ppm nitrite, with salanity of 1.026.

Assuming it is in fact the pH that is causing this problem, I have a few questions...

1. Could this in fact be the pH alone that is causing the fish not to have an appetite?

2. Would adding a pH buffer such as Kent Marine Superbuffer dKH help in decreasing massive fluctuation of pH? (I may or may not have added 1/4tspn already....)

3. I'm feeding him Ocean Nutrition Prime Reef Flakes from my LFS. Should I switch to something with garlic?

I do realize it may be somewhat humorous to ask for help on the "go-to" hardy fish, but I don't want this to be a reoccurring issue with future livestock..

[btmedic04]

the damnsel has probably increased CO2 in he tank, hence the drop in ph. get some more water movement at the water surface to help with oxygen exchange. also was this tank cycled before he was added?

[Coats]

Yeah for a few weeks.

[Sk8r]

That species can barely tolerate a 55 gallon tank and does better in 100 gallons. Trade him for a much more sedentary small fish.

[Mark9]

That species can barely tolerate a 55 gallon tank and does better in 100 gallons. Trade him for a much more sedentary small fish.

That seems a tad high, liveaquaria says 30g.

[Sk8r]

Clowns do better in smaller spaces than most damsels do. While the yellowtail is a bit smaller than some, it's still not likely to do well in a 20. Most damsels spend most of their lives within 2 feet of home, and if you don't crowd him he may be ok, but they can get very cranky with neighbors if crowded. If he's your only fish, or the only one with tankmates like gobies or blennies that don't challenge him, he may be ok. The yellowtail is as aforesaid pretty laid back and smaller than most as an adult.