What are your water perameters? Tank temperature?
You say added coral a month ago, did you quarantine them?
Is it just fish dying, or are any corals/inverts also effected?
Other, more informed folks will get back to you I am sure, but my guess if it's just fish is some sort of disease. You say they were running into rocks and seizing, were they rubbing themselves against the rock, or shaking their heads?
Were they hiding during the day, or also when the blue lights were on?
Any swimming into flow, powerheads, filter, ect?
Do you still have any of their bodies? If so, I'd suggest a freshwater dip to check for flukes just to eliminate one possibility.
Water parameter for last 4 weeks (i do 19L WC everyweek):
Mg = 1460, 1520, 1440, 1420
Dosing Mg 1 ml/day
Alk = 9.5, 9.5, 9.3, 9.1
Dosing Alk = 1 ml/day
Ca = 390, 370, 390, 360
Dosing Ca = 14 ml/day (devided by 9 timepoints per day)
Dosing Kalk = 30 ml/day (devided by 19 timepoints per day)
NO3 = 1, 5, 5, 5
PO4 = 0.01, 0.01, 0.01, 0.04
Salinity = 33 ppt
Temp = 25-26 using chiller
pH = before going to work 8.21 (3 hours before tank sunrise), return from work 8.32 (3 hours before tank sunset); photoperiod = 12 hours.
No coral QT. Dip protocol for coral: Revive, Bayer, Lugol, rinse.
Snails are ok. I have some cyano & gha. Could be some dino, idk.
Fish behavior:
Morning = 1/4 cube of frozen mysis + 1 drop of AF FishV
Then nori 1/6 sheets.
Midday : feeder dropping a little bit New Life Spectrum pellets + Ocean nutrition formula 2 pellets.
Afternoon: 1/6 cube of homemade reef chili (salmon, scallop, shrimp, a drop of brightwell aquatics garlic),
Then another 1/6 sheet of nori.
Normal behavior: all fish would race to feeding.
Began with small anthias being chased by bigger anthias during feeding (maintaining dominance position); suddenly it hit a rock and seizure, drifting with current. I put the anthias easily in acclimation box because of seizure condition. Other fish were still normal.
Minutes after being put in the box, that anthias swam back normally.
24 hours in the box was quite stressful then i let that one back to reef, only to found the next day it was died. Other anthias still eagerly ate food. A few days later bigger anthias won't come out during feeding then a few days later was found dead. Then one by one had the same fate. This hiding behavior occured during brightlight and blue light.
No rubbing on rock, no visible ich or velvet, no shaking head. No swimming near powerhead.
Looking at the first dying anthias i thought it was HLLE.
Last fish alive was YT, during morning feeding it was suddenly panick and swam thru a rock making him paralyzed then I got the chance to scoop him out into QT for PraziPro treatment. But 36 hours later it also died.
Post mortem dipped in fresh water (sorry idk what to look for this flukes)
