Bad luck with fish…

[sjk123]

initially I had 1 green chromis, 1 Kupang damsel and 1 Scooter blenny in a 100 gallon. All were happy and getting along no issues. 2 weeks ago purchased a lavender tang. Once he got settled he started attacking everything. After about 3 days i watched him kill the kupang damsel by crushing him in the corner. Immediately after he turned his attention to the chromis. The following morning the tang was no longer visible in the tank and was found dead between the rocks. No apparent reason as he was acting normal upon last look at tank.
The remaining fish are completely fine. Added 2 baby clownfish 3 days ago. This evening the chromis attacked aggressively and within an hour both clownfish were dead.

I’m getting really frustrated with the cycle of everything apparently killling each other. And don’t know what to do. Should I try to add a new damsel to counter the aggression of the chromis?

All water parameters are normal and the remaining fish again are completely healthy.

 

[rayadog]

So you have 1 chromis and 1 scooter blenny left? Do you quarantine? And could you? I would expect a chromis to be that viracious but I bet if you could remove them and return them as you add or after you add new fish; maybe even change up the rocks

 

[Ridgeback1]

I second the quarantine tank need--not just to keep out diseases, but also to let new arrivals settle in without stress of being instantly thrown into an established tank whose residents have territories already. Also, I have had success using an acclimation box. A few days in the box during introduction allows new and old fish to get used to each other without being attacked. Then after a few days, release the fish at night so it can find a spot to settle without being harassed. Some also use a mirror to occupy any boisterous current residents during introduction but I've never tried that. (The tang may have died from shipping stress (including ammonia toxicity) or disease but unclear until we know your quarantine practices, if any).

 

[Mr. Mojo Rising]

It sounds like you are adding territorial fish, how is the rock work in your tank? Do you have enough rocks and enough hiding spaces for each fish to have his own territory?

 

[Aqua Ultraviolet]

initially I had 1 green chromis, 1 Kupang damsel and 1 Scooter blenny in a 100 gallon. All were happy and getting along no issues. 2 weeks ago purchased a lavender tang. Once he got settled he started attacking everything. After about 3 days i watched him kill the kupang damsel by crushing him in the corner. Immediately after he turned his attention to the chromis. The following morning the tang was no longer visible in the tank and was found dead between the rocks. No apparent reason as he was acting normal upon last look at tank.
The remaining fish are completely fine. Added 2 baby clownfish 3 days ago. This evening the chromis attacked aggressively and within an hour both clownfish were dead.

I’m getting really frustrated with the cycle of everything apparently killling each other. And don’t know what to do. Should I try to add a new damsel to counter the aggression of the chromis?

All water parameters are normal and the remaining fish again are completely healthy.

I wouldn’t add another damsel to deal with the chromis. You could end up with two aggressive, territorial fish instead of solving the problem.

A single green chromis can become territorial, especially in an established tank. Adding very small clownfish to its territory may have triggered the aggression. The tang’s behavior is also consistent with territorial aggression, although its sudden death could have had another cause.

For now, I’d stop adding fish and let the remaining fish settle. When you eventually add another fish, rearrange some rockwork first and use an acclimation box if possible. This can disrupt established territories and give the new fish a better chance.

 

[aussiejohnny]

initially I had 1 green chromis, 1 Kupang damsel and 1 Scooter blenny in a 100 gallon. All were happy and getting along no issues. 2 weeks ago purchased a lavender tang. Once he got settled he started attacking everything. After about 3 days i watched him kill the kupang damsel by crushing him in the corner. Immediately after he turned his attention to the chromis. The following morning the tang was no longer visible in the tank and was found dead between the rocks. No apparent reason as he was acting normal upon last look at tank.
The remaining fish are completely fine. Added 2 baby clownfish 3 days ago. This evening the chromis attacked aggressively and within an hour both clownfish were dead.

I’m getting really frustrated with the cycle of everything apparently killling each other. And don’t know what to do. Should I try to add a new damsel to counter the aggression of the chromis?

All water parameters are normal and the remaining fish again are completely healthy.

re arrange your tank before putting anything in so that no one has a territory yet..
i have a clownfish who im sure would not allow any fish in her tank ,,she has so far pushed corals off rocks pushed whole rocks over bangs the heater if she wants attension pulls snails off the glass throws them across the tank ...i re arranged my tank in hope she would accept another fish ...she re arranged my arrangement ..she lives by herself now watches the red tail shark in the tank next to her ..both nasty bullys ..but i love them both

 

[Damage12]

It sounds like you are adding territorial fish, how is the rock work in your tank? Do you have enough rocks and enough hiding spaces for each fish to have his own territory?

This^^^