Distressed green chromis in new tank

One of my four green chromis went missing last night and I haven't found him today. A second was swimming low in the 150 gal tank and tipping to the side. Occasionally he would swim back up to other levels but he looked to my inexperienced eye in distress.

The salt water, LS, and LR have been in the tank for about three weeks. The chromis were added Tuesday a week ago (about 10 days). All water tests have been normal to date.

This morning I checked for ammonia and nitrates (both completely normal, no sign of a spike). I rechecked the salinity with a hydrometer. It was either on the low range 1.020 or slightly lower (1.019). Mind you, the hydrometer requires the patience of Job (which I haven't got) because it swings in its readings from above 1.028 to below 1.016. I use the tapping to get rid of air bubble, rinsing before use, and reading on a level surface. I will get a refractometer this weekend. However...back at the fort...

So I guessed that the salinity might be too low and/or a partial water change for the fish might be needed. I understand that you wait for an ammonia spike in a new tank but the fish are distressed and ammonia is not the problem.

So I pulled the distressed fish out and put him into a quarantine 10 gallon tank (in about 3 gallons) of slightly saltier water (1.0121). I went to the grocery store and bought reverse osmosis water. I am about to remove about 10 gallons of tank water and replace it with premixed 1.022 water to see if this will help.

Any suggestions?

 

Chromis are schooling fish. If you don't keep them in large enough schools to "dilute" aggression, the dominant fish will harass its competition until it's the only chromis left in the tank.

 

Well, I am guessing that if 4 chromis wasn't a large enough school then 3 will be even less successful in preventing aggression.

I am somewhere in my cycling...waiting for an ammonia spike...so I don't think I can add more fish yet. I do have hiding places.

 

It's quite possible that your fish are dying as a result of the cycle but if they do make it through, don't be surprised if the dominant fish picks off the remainder of its competition. I wouldn't add any more fish at all until your tank has completed its cycle.

 

+1 great advice and spot on!