Overnight mystery of fish and corals

[jwwill0]

On Friday afternoon, I did about a 4 gallon water change on my 55g tank. Everything seemed fine. I also added another MaxiJet 600 PH to increase the total flow to 635 gph. The new salt water was being kept in a spare 10g tank with a power filter on it to aerate the water. SG and temp was very close to the main tank.

Tank inhabitants:
1 small sailfin tang
1 false percula clowns
1 firefish goby
1 small red brittle star
1 cleaner shrimp

1 Xenia
1 toadstool mushroom
small amount of glove polyups
1 small colt

Cyano breakout within last couple of weeks

Everything has been in the tank at least a week, most much longer, and no signs of problems

Saturday morning, Sailfin tang is dead. All corals are closed. The Xenia seems "shriveled" up a bit. Other three fish and inverts seem ok.

Water tested ok.
Amm = 0
Nitrite = 0
Nitrate = 15 (was 20ppm before water change, and had been for awhile)
Temp = 79
SG = 1.024
pH = 8.2

No spots on any fish

Any ideas??

 

[fishfreek]

In partuclar how long had you had the tank? Had you seen it eating well? What where you feeding it?

What do your corals look like now? many will be closed in the morning prior to lights on.

How is the new PH in pacement to the corals? Is it blowing directly on any of them? Is the xenia still getting a good current around it?

 

[jwwill0]

The tank has been up for about 1 1/2 months. The sailfin was added two weeks ago and has seemed happy and healthy since then, even yesterday afternoon. All fish have been eating very well. I was feeding mysis shrimp and a dried seaweed clip. The sailfin would eat both, as well as graze on algae in the tank. Corals still look the same, closed up.

The new powerhead was placed about 4 inches from sandbed, flowing straight out over the sandbed. I wanted to reduce any deadspots because of the cyano outbreak. It was not blowing directly on any of the corals. All had good flow. Some were towards the top, others on the bottom. I unplugged the new ph this morning for awhile, and nothing changed. I plugged it back in about two hours ago, and still no change.

 

[kidafius]

did you decholorinate the water? Sorry to ask, but if forgotten, it could be really dangerous.

 

[jwwill0]

Yep, dechlorinated water. Tank water is dechlorinated tap water (I know, I now only use RO/DI) The makeup saltwater was mostly the same dechlorinated tap water, with about 30% new RO/DI water.

 

[reefrunner69]

I unplugged the new ph this morning for awhile, and nothing changed. I plugged it back in about two hours ago, and still no change.

The reaction to the new powerhead may be slow in coming, once disturbed it may take them a day or two to get used to the new current, and if the new current is removed, it could take a day or two to return to normal. The PH, itself could be the cause of the tangs death. The new current could have blown it into a rock, or some other trauma.

 

[jwwill0]

One other thing, the sailfin's top and bottom fins appeared more black when I found it dead. Normally they are yellow.