Mysterious deaths

[LiamPM]

All my tangs are small or juvenile because I’m upgrading to 300 gallon next year

The size of the fish currently doesnt really change their behaviour too much - a territorial fish is that even when small in the majority of cases, its their nature - a defence mechanism to protect their feeding patch. Its one of the reasons i personally am not a fan of keeping fish with a future upgrade in mind. Its not always about the fish's swim space and aggression and territory is often overlooked - Ive had tiny tangs become the rulers of the tank when 4-5 inches smaller than the next fish.

You have all the tell tale signs of aggression being the killer i think and the likes of a camera, or a few hours in front of the tank with a coffee and book are what id recommend, see if you can spot anything physically happening.

 

[TerryG]

Update for everyone! Came home from work and Thompson tang is now dead after 3 successful weeks in tank. You were all right it’s aggression. My powder blue tang has become a murderous *******. All though initially he was ok he has since changed to a devil. He will need to be removed from the system

 

[TerryG]

The size of the fish currently doesnt really change their behaviour too much - a territorial fish is that even when small in the majority of cases, its their nature - a defence mechanism to protect their feeding patch. Its one of the reasons i personally am not a fan of keeping fish with a future upgrade in mind. Its not always about the fish's swim space and aggression and territory is often overlooked - Ive had tiny tangs become the rulers of the tank when 4-5 inches smaller than the next fish.

You have all the tell tale signs of aggression being the killer i think and the likes of a camera, or a few hours in front of the tank with a coffee and book are what id recommend, see if you can spot anything physically happening.

You are spot on there! My powder blue tang has gone on a murder frenzy!