Fish Die Off

[Jyanik]

I am new to the hobby and just dipping my toe in the water so to speak. I have a 45 gallon FO tank. Rema canister filter and Penguin 400. The tank is 5 months old with an established cycle. I started slowly and introduced 2 yellow tail damsels and ran that way for about 2 months. When I got a diatom outbreak I added 4 red legged hermits, a sand sifting star, an a dozen asterea snails for clean up crew. everything was great so far. 3 weeks ago I bought a Coral Beauty Angel and a Yellow Coris Wrasse and introduced them. All the livestock appeared healthy and were eating just fine. After 2 weeks I found the angel dead on the bottom of the tank. Yesterday the wrasse was dead under the sand. One of the damsels is nowhere to be found and the other is still swimming. All the clean up crew seem to be ok. Specific Gravity has been maintained at 1.025 and ammonia and nitrites are at 0. Low nitrates (10ppm) and pH of 8.1. I use RO water and do weekly changes of 10-20%. Anyone have any ideas what might be wrong? Could it be a disease? How do I find out? As I said, the fish appeared healthy and were eating and swimming fine. Any help would be appreciated. I'd like to continue in the hobby but this is frustrating as I thought I had things under control.

 

[crister13]

Did they have anything visually unusual? Are you POSSITIVE that your sand sifting star is ok because it either died of starvation or will die of starvation. I would return it as they eat microfauna in the sand which is beneficial and he will die in a 45. They die in established (2+yrs) 125s alot. He probably died and spiked ammonia.

 

[Jyanik]

Thanks for the reply. I've already been warned about the star but he is alive and well and I've been feeding him algae wafers and brine shrimp pellets to keep him alive. I do plan to move him out. Nothing unusual about the fish when I got them. They didn't have a blemish on them, acclimated to the tank quickly, ate like horses and were active right up until they showed up dead. I'm mystified as to what's happening.

 

[crister13]

Could you possibly have stray voltage????? How did you acclimate them????? When were they introduced?????

 

[Jyanik]

No stray voltage. Checked that today. I acclimated via drip method over about an hour. Both the wrasse and the angel were introduced at the same time about 4 weeks ago. The damsels have been in the tank for months.