Fish aggression, what steps to take?

[Colin_S]

Hi guys, So recently i have had 2 fish killed. So i'm wondering what is your giud in preventing this? Here's what happened.

I had 2 yellow tail damsels (YTD). After a period of time, one of them was being bullied by only the other YTD, She stopped eating and looked a bit beaten up. I took her out of the DT and into a HT, for about 8 weeks. Medicated her for the cuts and got her feeding well. So i introduced her back to the tank and straight away the other YTD went straight for her, pushing her into the clowns area and then they started. I decided to take the aggressive YTD out into the HT, but the next day the bullied one was dead, so i put the other YTD back in the DT, i then broke down the HT.
About 3 weeks later (yesterday) after 2 weeks of braking down the HT my Chromis, which i have had in the DT from the begining (2+yrs) along with the clowns and was eating so well was killed by the clowns in front me and so aggressively. Both the male and female clown would seek chromis out and just attack him. So much damage was done he couldn't swim and was floating around getting attacked constantly, and pretty much waiting to die, i had no option other than to put him out of his misery.
The only thing i can think off why the chromis might have gone dazed and into the clowns area is its is my tank got too hot. it was at 25.5 (i think) and i try and keep it at 24.5-25. My daughter was home from school as a precaution and likes to have the heating on high and all the doors shut and no windows open.

Now if my HT was still up and running , maybe i could have saved him if i got to him earlier, but what would have stopped him getting attacked straight away once re-introduced like the YTD did.

So, how do you deal with aggression from fish that have been housed together for years?

 

[NS Mike D]

fish aggression is, but not limited to, territorial. While fish per inch rules serve their purpose, I also thing a tank needs to take into consideration fishes' territorial needs; lots of space for swimmers as well as nooks, crannies and caves.

Chromis like to swim about during the day but when stressed or at night have their own safe hiding spots which they will defend aggressively.

I have witnessed my female ocellaris clown decide she was done with him and go ballistic on its mate until it was so stressed out I couldn't save him. She would stalk him even if he swam away and hid in a rock, just hovering to find a way, obsessed, to get to him.

I don't even go near damsels after my first experience. The one had when I first set up my tank reined terror on the tank, claiming the entire tank its territory.


Sorry, I don't have a solution, as I don't think there is much you can do other than find one a new home once the friendship is over. If the territory skirmish is not resolved quickly between the parties involved, I am afraid it's a Darwinian life or death situation for them.

I think all you can do if provide proper space and territory they can call home, make sure they are compatible before adding to the tank and from there it's luck of mother nature.

sorry for your losses. It's hard to accept the finality of the behavior. I harbor no hard feelings for my clown. Like the famous movie line. "it was business". She is magnificent and for the past two years, a good to her new mate. That could change tomorrow.

 

[Jose Berry]

I love my 225G tank i have a variety of fish
Our Fish
Gill :Moorish Idol (1/2020)
Hawk :Flame Hawk Fish (5/2020)
Passer Angel (5/2020)
Oracle :Imperator Angel (2/2020)
Thing 1 :Midnight Clown
Thing 2 :Midnight Clown
Marlin :Tomato Clown
Coral :Tomato Clown
Bubbles :Yellow Tang
Dory :Blue Hippo Tang
Koi :Yellow Eye Kole Tang (5/2020)
Vlamingi Tang (5/2020)
Kevin :Lawnmower Blenny (5/2020)
Woop :Midas Blenny (5/2020)
Goby1 :Mandarin Goby
Goby2 :Mandarin Goby (5/2020)
Bloat :Green Spotted Puffer
Bloat Jr :Green Spotted Puffer

I’ll tell you from personal experience that some of these are considered aggressive and ive seen it where fights broke out from the first few days I brought them in. It’s been a few weeks but the best thing I can say is space and how your rocks are set up. I have mine in a lagoon T shape with plenty of hiding spaces. Territory is important for a few fish and if aggression is happening a change in the layout of your tank is sometimes needed. I’m no professional or anything I’m just imputing what I’ve done and what I’ve witnessed.

 

[eatbreakfast]

What size is your display? What kind of clowns? How old are the clowns?

 

[Luis1992]

Rearranging rock is the fastest thing to stem some aggression. Mirror trick works wel with tangs.

 

[WildChurchMonkeys]

Rearranging rock is the fastest thing to stem some aggression. Mirror trick works wel with tangs.

+1 and I would add that if you can remove the fish from the DT during the rearranging, you can reintroduce the fish from least aggressive to most aggressive over a period of time, to give your timid fish more time to stake claim to a spot in your tank.

 

[CheckeredPants]

Damsels, Chromis, and Clowns are all in the Chromis/Damsel genus which can all be aggressive, territorial, and a danger to their own and others in a tank.
To me you’re dealing with a bunch of Damsels establishing their pecking order as they really settle into your tank.
I loved my Fijian Devil Damsel for years but decided to not put her into my newest setup for fear of what you’re dealing with and since they are near impossible to catch.

 

[Colin_S]

What size is your display? What kind of clowns? How old are the clowns?

150g, Percular Clown and 2.5yrs - 3yrs. There is enough hiding spaces for the fishes, with plenty of LR.. I have re-arrange the rockwork before, but now its cemented in place, so i can only move abut 40% of it.
i would be interested if anyone has taken out the aggressive fish for a period of time and re-introduced it to see what the behavour is after that.

 

[PerplexyHexy]

Whenever I have fish aggression introducing new members, I use a mirror... It keeps the fish interact with the mirror... after a few weeks they have forgotten there was a new member... works every time for me... especially with tang aggression... use a fairly large mirror that covers a good portion of your tank...

 

[Colin_S]

Thats the plan going forward...

 

[mickeysreef <*))))<]

how long do you leave the mirrors up?

 

[PerplexyHexy]

I kept up for at minimum a month... lol... maybe thats too long, but it worked everytime for me after that period of time

 

[mickeysreef <*))))<]

yellow tang was ***** going after my new powder blue. sailfin wasnt really bothering him but now he wont get off the mirror lol

ive got a tiny hippo blue, he is just hiding in the back towards the top, i dont think anyone has even seen him

 

[PerplexyHexy]

It will work... keeps them occupied and not worry about others until they forget

 

[mickeysreef <*))))<]

yeah I can see less aggression just after a day. powder blue was injured by yellow even after mirrors but just a fin injury he is eating today so looks good.

tiny hippo is hilarious I don't think the other fish even understand what he is. he is hanging out with the damsels and the tangs just swim right by him

 

[Mikeltee]

Only fix is get rid of the aggressor. Do your due diligence in shopping for an animal. Make sure it has a peaceful temperment. If it does not, see why it does not. In many case it likes to be the only one of its species.

Even if you have all peaceful temperment animals, they will still become aggressive if they dont have the required space. I once had a hippo tang in a 180gal. One day I came home and all my fish were dead except him. He had a spaz attack and just ran through that tank crazily and it gave all the other fish heart attacks. What did I do to fix the problem? Gave the tang away to a guy with a 600gal tank and never bought another hippo. Learn from your mistakes. Take a proactive approach and get rid of them now before they are all dead.

 

[PerplexyHexy]

just stick with the mirror for a month man... they will be fine... lol!!!

 

[mickeysreef <*))))<]

Only fix is get rid of the aggressor. Do your due diligence in shopping for an animal. Make sure it has a peaceful temperment. If it does not, see why it does not. In many case it likes to be the only one of its species.

Even if you have all peaceful temperment animals, they will still become aggressive if they dont have the required space. I once had a hippo tang in a 180gal. One day I came home and all my fish were dead except him. He had a spaz attack and just ran through that tank crazily and it gave all the other fish heart attacks. What did I do to fix the problem? Gave the tang away to a guy with a 600gal tank and never bought another hippo. Learn from your mistakes. Take a proactive approach and get rid of them now before they are all dead.

it's a 210. let's hope the extra 30 gallons makes a difference!!!!

 

[Hannible123]

Sorry for the basic question but do you guys place an actual mirror inside the tank or can I use a mirror sheet and tape outside the tank?

 

[mfinn]

Sorry for the basic question but do you guys place an actual mirror inside the tank or can I use a mirror sheet and tape outside the tank?

I tape a mirror to the outside of the tank.