Aggressive Harlequin Tusk

Waters · May 20, 2016

I have a Tusk that is now roughly 3.5 to 4 inches and has become increasingly aggressive. Any fish added after him is chased and attacked. Currently he is in the sump due to his latest attacks on a new Coris wrasse. Unfortunately the tusk is my favorite fish. What are my chances that his sump time out will mellow him out? How long does he need to be left in there before I can attempt to re-introduce him to the DT? I really don't want to get rid of him but I also don't want the rest of my fish (mainly wrasses) to be constantly chased. The sump is only 26 gallons split into three compartments so he can't be kept in there long term.

Reef Junky150 · May 20, 2016

Did you add new fish during lights out?

eatbreakfast · May 21, 2016

Unfortunately aggression rarely gets any better. Sump timeouts work better for fish not closely related, with mainly wrasses in the tank aggression will likely continue after being reintroduced.

Other semi aggressive fish would be good tankmates. If you can find Coris wrasses that are already big can be an option, but a social acclimation box for introducing new fish is a good idea.

Waters · May 21, 2016

Thanks for the advice. Yes, the lights were out when introduced. I did use an acclimation box for the Coris which the Tusk showed absolutely 0 interest in. I think he was more afraid of the box being in the tank to care about the fish. The Coris wrasse is about the same length of the Tusk....maybe I should have gone a little bigger. The difference between the Coris and my smaller wrasses is the Coris refuses to go and hide....he just hangs out in the corner until the Tusk sees him and attacks. I will give it a few days and try putting the Tusk back in. I have read a lot about using a mirror to curb aggression....is that worth trying?

eatbreakfast · May 21, 2016

Using a mirror for a few days can keep the tusk focused on it's reflection and give the new introduction a chance to settle.

Waters · May 21, 2016

Ok, thanks. I will give the mirror a try along with the brief time out. I just added the Tusk back to the display tank tonight. That gave the new Wrasse a couple of days to settle in. He was eating and swimming around normally but disappeared into the live rock/sand sometime today. If he is going to hide for an extended period of time, it made no sense to keep the Tusk in the sump. After removing the Tusk, it seemed like all the rest of the smaller wrasses started harassing each other...really strange. Almost like the Tusk was keeping everybody else in line lol.