Green Chromis Help

[Jaxs]

Hey Guys I have a new setup 45 gallon tank here. Its my first personal tank but I have been around the hobby from my dad for a while now! So long story short I Introduced 3 green Chromis about three days ago! This morning one was dead on the sand bed. Now the tank has been running for two months. I have one clown, and two cardinals already. I did a water test just to make sure everything was ok. everything was normal with nitrates at 5. And all the other fish seem happy and have a lot of energy. I thought they were very docile fish but now I'm reading they kill each other off sometimes? Was wondering if this is common because I'm nervous its something with my water. There was a large chunk taken out of the fish when I saw him dead on the sand bed, but that could have been from a crab after he died.

 

[DSC reef]

Green chromis can take eachother out. It happened in our 75 reef tank. After a few months we went from 3 down to one. Now the single chromis has been fat and happy for years. Banghai cardinals can be aggressive and territorial too.

 

[nautical_nathaniel]

The large chunk taken out of it was probably from something trying to eat it after it died, totally natural and actually somewhat good because that's less nutrients breaking down and impacting water quality.